Ex-chancellor Ken Clarke has been knocked out of the race to become the next leader of the Conservative Party.
The self-styled "big beast" came fourth in the poll of Tory MPs, gaining 38 of the 198 available votes.
Of his rivals, David Davis came top with 62 votes, followed by David Cameron on 56 and Liam Fox on 42.
The three remaining candidates go through to another vote by Tory MPs on Thursday. That will select the two who go to a ballot of all party members.
Mr Davis brushed off claims he was leaking support to his rivals, having previously claimed the backing of at least 65 MPs.
He said he was very grateful to his colleagues for their support, but added that the numbers showed there had been some "tactical voting".
"I think the fact is I'm top of the poll - the highest number of Tory MPs - these are the people who know me and know the other candidates - these are the people who have selected me as first choice."
Commenting on his result, Mr Cameron said: "It's a very good result - it's better than I expected. My team have worked incredibly hard. We've had a very good response."
He said he would be talking to Mr Clarke and his supporters "and asking them to back me in this all important second ballot".
Dr Fox said: "It's a very good result for us - we polled way above what anyone was predicting. We are going into the next round with lots of momentum."
Mr Clarke said he was "obviously very disappointed" with the result, but thought he had "contributed to the debate in a positive way".
Third time unlucky
He said he would be loyal to whoever leads the Tories, but he hoped they would "pay regard to my advice" on how the party should conduct itself.
Commenting on his failure in the ballot, he added: "I think it sends a message that they are looking for a younger leader probably, but I don't think my age was actually remarkably relevant."
BBC Political Editor Nick Robinson said Mr Cameron had "undoubtedly won this contest today" and it would be "hellishly difficult" for Mr Davis to regain the momentum he had previously.
With many of his supporters now expected to switch to Mr Cameron, Mr Clarke is expected to sleep on the result before deciding to publicly back any of the remaining candidates.
It is the third time Mr Clarke has lost a contest to become Tory leader, having stood in 1997 and 2001.
Europe stalling point?
He had the most experience of all the candidates, having served as chancellor, home secretary, education secretary and health secretary under the Thatcher and Major governments.
But Mr Clarke's long-term support for further European integration has alienated many within his party.
His role as vice-chairman of tobacco firm BAT has also been controversial.
Speaking on BBC Radio 4's World Tonight, Tory MP Stephen Dorrell MP, who voted for Mr Clarke in the poll, said he would be switching his allegiances to Mr Cameron.
And Eleanor Laing MP told the programme she had spoken to four Mr Davis supporters who would now be switching to Dr Fox.
Meanwhile, Adam Holloway MP said he had defected from Mr Davis to Mr Cameron in Tuesday's vote.
But he told BBC Two's Newsnight of his "niggling doubt" that Mr Cameron would be "eaten alive" by Prime Minister Tony Blair and Chancellor Gordon Brown.
The final result of the party members' ballot is expected on 6 December.
Michael Howard, who has formally resigned as leader, will carry on in a caretaker role until then.