BBC political correspondent Chris Mason says the expectation was there would be "a lot of ganging up" on Boris Johnson.
But he says what was actually striking was "how much ganging up there was on Rory Stewart".
That's because Mr Johnson is "ahead by a country mile" and so the "battle now is to be second" on the ballot.
The gap between the current second place candidate and fifth place is just 13 MPs' votes, he says.
"I just wonder if Rory Stewart's 'big mo' might have eased off after tonight," he says.
EU thinks no-deal Brexit 'increasingly likely' after tonight
Katya Adler
Europe Editor
EU politicians across the continent were dipping in and out of the debate. The comments I've heard so far off-the-record have not been particularly complimentary.
The EU simply thinks that most of those leadership candidates are not being realistic.
EU leaders are preparing a united, determined front when it comes to the idea of renegotiating the Brexit deal, and the answer is no.
Even if, come the autumn, the EU were to be tempted to reopen some of those questions such as the Irish backstop, those conversations could never be finished by 31 October - the date by which most of those leadership candidates want to leave the EU.
That's why this evening the EU thinks the idea of a no-deal Brexit is becoming increasingly likely.
When it comes to the border, there are three key
problems to solve - how do you keep the United Kingdom together, how do you preserve the integrity of the
EU single market and how do you prevent any sort of border controls being introduced?
Boris Johnson suggested he could use something called Article 24 of GATT to
keep trade free. Acronyms aside, that requires both sides to agree so it isn’t going to
happen in the event of no deal.
Jeremy Hunt and Sajid Javid suggested
technology could be used to avoid the need for the controversial backstop. But the EU has
said repeatedly that there is no technology in use anywhere in the world that
will keep the border as open as it is now after Brexit.
Four of the five candidates committed to leave the EU by -
or not longer after - 31 October.
Time is short, though. The new prime minister will not be in
place until the end of July and then all of the relevant institutions in the UK
and EU go on holiday until September.
In September, you then have several weeks
of recess for party conference season in Britain, so no real work is likely to get done
until October.
There is then only the rest of that month to do any negotiation,
ratification and legislating, so the chances of getting anything through by Halloween look slim.
Justice Secretary David Gauke, who is backing Rory Stewart, says tonight's debate demonstrated he is a "strong, credible, serious candidate".
Asked if Mr Stewart has peaked, he says: "It's only just started.
"More and more members of parliament are looking at Rory and saying 'actually he is the person that we want to put through in the final round, the best person to take on Boris Johnson'."
Questioners not happy...
Mark, from Belfast, who asked a question during the debate on the Irish border, says he "didn't really" get a straight answer.
"To be honest, I wasn't really expecting one," he adds.
James, from Oxford, who asked about tax reform, says the evening's debate resembled "five school kids in a playground" arguing with each other.
The event, he says, was "quite embarrassing for the Conservatives", but on balance he was happiest with Jeremy Hunt's answer.
Leadership 'still Johnson's to lose'
Financial Times chief political correspondent tweets...
Live Reporting
Paul Seddon, Victoria King, Joseph Lee and Dulcie Lee
All times stated are UK
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Latest PostRecap: And then there were five...
Thanks for joining us for our live coverage of another big day in the Tory leadership race, following the second MPs' ballot earlier.
The field has now been cut to five, with former Brexit Secretary Dominic Raab knocked out of the race after only gaining 30 votes.
Boris Johnson remains the frontrunner, having upped his tally to 126 votes from the 114 he received in the first ballot last week.
The remaining candidates then clashed over Brexit, their tax pledges, climate policy and other areas in a televised debate hosted by the BBC.
The process will continue tomorrow with another ballot of Conservative MPs, after which the bottom-placed candidate will be eliminated.
Teen challenges Tory rivals on climate change
Scottish climate striker Erin, 15, asked the leadership contenders to commit to net zero admissions by 2025. Read more.
Watch: Stewart admits he was 'lacklustre'
'Battle is for second place'
BBC Radio 5 Live
BBC political correspondent Chris Mason says the expectation was there would be "a lot of ganging up" on Boris Johnson.
But he says what was actually striking was "how much ganging up there was on Rory Stewart".
That's because Mr Johnson is "ahead by a country mile" and so the "battle now is to be second" on the ballot.
The gap between the current second place candidate and fifth place is just 13 MPs' votes, he says.
"I just wonder if Rory Stewart's 'big mo' might have eased off after tonight," he says.
EU thinks no-deal Brexit 'increasingly likely' after tonight
Katya Adler
Europe Editor
EU politicians across the continent were dipping in and out of the debate. The comments I've heard so far off-the-record have not been particularly complimentary.
The EU simply thinks that most of those leadership candidates are not being realistic.
EU leaders are preparing a united, determined front when it comes to the idea of renegotiating the Brexit deal, and the answer is no.
Even if, come the autumn, the EU were to be tempted to reopen some of those questions such as the Irish backstop, those conversations could never be finished by 31 October - the date by which most of those leadership candidates want to leave the EU.
That's why this evening the EU thinks the idea of a no-deal Brexit is becoming increasingly likely.
Watch: Javid brought 'unity'
Watch: Stewart has 'only just started'
Watch: Hancock on Johnson's Muslim great-grandfather
Watch: Nicky Morgan on Gove's 'clear' Brexit plan
Rivals wanted to put Stewart 'back in box'
Metro deputy news editor tweets...
'Plenty of verbal fisticuffs'
Laura Kuenssberg
BBC political editor
Moments like this in any political campaign really do matter.
This is nothing less than a public job interview for the biggest role in the land.
As you would expect, there were plenty of verbal fisticuffs tonight, plenty of arguments, maybe not so many real and detailed answers.
But what they said on the stage, how they interacted with each other will make a difference as Tory MPs decide tomorrow who they are going to back.
Gove: I won the debate
Reality Check
How do claims about the Irish border stack up?
When it comes to the border, there are three key problems to solve - how do you keep the United Kingdom together, how do you preserve the integrity of the EU single market and how do you prevent any sort of border controls being introduced?
Boris Johnson suggested he could use something called Article 24 of GATT to keep trade free. Acronyms aside, that requires both sides to agree so it isn’t going to happen in the event of no deal.
Jeremy Hunt and Sajid Javid suggested technology could be used to avoid the need for the controversial backstop. But the EU has said repeatedly that there is no technology in use anywhere in the world that will keep the border as open as it is now after Brexit.
Shout out to the Reality Check team
BBC News editorial director tweets...
Reality Check
How does the deadline talk stack up?
Four of the five candidates committed to leave the EU by - or not longer after - 31 October.
Time is short, though. The new prime minister will not be in place until the end of July and then all of the relevant institutions in the UK and EU go on holiday until September.
In September, you then have several weeks of recess for party conference season in Britain, so no real work is likely to get done until October.
There is then only the rest of that month to do any negotiation, ratification and legislating, so the chances of getting anything through by Halloween look slim.
Did Gove's father 'lose his business'?
Daily Mirror politics correspondent tweets...
Did all candidates agree to Islamophobia inquiry?
Executive editor, politics, HuffPost UK tweets:
Gauke: Stewart is a 'serious candidate'
BBC News Channel
Justice Secretary David Gauke, who is backing Rory Stewart, says tonight's debate demonstrated he is a "strong, credible, serious candidate".
Asked if Mr Stewart has peaked, he says: "It's only just started.
"More and more members of parliament are looking at Rory and saying 'actually he is the person that we want to put through in the final round, the best person to take on Boris Johnson'."
Questioners not happy...
Mark, from Belfast, who asked a question during the debate on the Irish border, says he "didn't really" get a straight answer.
"To be honest, I wasn't really expecting one," he adds.
James, from Oxford, who asked about tax reform, says the evening's debate resembled "five school kids in a playground" arguing with each other.
The event, he says, was "quite embarrassing for the Conservatives", but on balance he was happiest with Jeremy Hunt's answer.
Leadership 'still Johnson's to lose'
Financial Times chief political correspondent tweets...