The secretary of the Tories' powerful 1922 committee said Theresa May gave a "first-rate performance" in front of the gathered MPs on Monday night.
The Prime Minister appeared before the committee of backbench MPs, which oversees the selection of Tory leaders, to field questions relating to the result of the General Election.
The Tories lost their majority after the vote, and a number of MPs' seats were taken by candidates from other parties.
Despite last week's election disaster, committee secretary Bob Blackman told Julia Hartley-Brewer the Prime Minister set the correct tone for the meeting.
He said: "She [Theresa May] made clear she was apologetic for the way the campaign was run and for those who lost their seats.
"What she made clear was the party would be more inclusive with backbenchers as it goes forward.
"That was warmly welcomed - the style which had been adopted was excluding people, and I think this will change.
"She gave a first-rate performance last night and the regret was if she had shown that in the campaign, we wouldn’t be sat here."