Wes Streeting's hopes of becoming the next Labour Prime Minister took a blow on Monday evening as a poll of members roundly rejected him.
A majority said Mr Streeting was wrong to resign as Health Secretary last week in a bid to challenge Sir Keir for the Labour leadership - with almost six in 10 thinking he made a mistake.
And nearly seven in 10 members would even root for Sir Keir to beat Mr Streeting in a leadership contest, they told pollsters YouGov, despite nearly 100 MPs calling for the PM's notice after Labour took a beating at the local elections.
Just 15 percent said they would back the challenger.
Mr Streeting confirmed last week he intends to oppose Sir Keir after criticising the PM for lacking 'vision' - yet failed to formally trigger a leadership bid, with critics suggesting he had failed to gather enough support to do so.
And the polling reveals the MP for Ilford North would likely be thrashed in a leadership contest by Andy Burnham, Angela Rayner and Ed Miliband.
But there was better news for Andy Burnham in his quest to take over from Sir Keir - with 47 percent of party members ranking the Greater Manchester Mayor as their first choice, compared to 31 percent for the current resident of No10.
And in a direct contest between the two, nearly six in 10 Labour members would back Mr Burnham against Sir Keir, with just 37 percent saying they would vote to keep Sir Keir in situ.
Wes Streeting's popularity among Labour Party members is not enough to see him take the top job in a leadership election, a poll has suggested
Andy Burnham, current mayor of Manchester and aspiring MP, was recorded as the first choice for leader by almost half the members who voted
The poll, of 706 Labour members, is the first since Mr Streeting resigned and set the leadership hare running last Thursday, 14th.
Mr Burnham is readying himself to compete in a dramatic by-election which could see him return to Westminster to fight Sir Keir for the leadership.
But more than six in 10 Labour members think the PM should stand down before the next general election no matter what.
And even if Mr Burnham were to lose the battle for the Makerfield seat next month, the polling reveals Labour members have similarly positive views of those who may eventually throw their hats in the ring to challenge Sir Keir.
Nearly three-quarters of Labour members have a favourable view of Mr Burnham, 80 percent of Ms Rayner, 77 percent of Mr Miliband and 73 percent of Yvette Cooper.
While two-thirds of party members believe Sir Keir has done a good job as Prime Minister, just over a quarter think Labour are likely to win in 2029 if he remains as leader.
But in contrast, 74 percent think the party is likely to win the next general election if Mr Burnham takes the Labour crown.
And revealing the depth of positive feeling for the so-called 'King in the North', Labour members are less optimistic about the party's fortunes under Ms Rayner, Ms Cooper, Mr Miliband and Mr Streeting.
Under Labour's rules, a leader can be challenged if at least 20 percent of the party's MPs (80) nominate a single candidate to succeed him. Labour members then vote for their preferred candidate using a ranking system.
While Mr Burnham will be buoyed by the poll results, he was today forced to quell a Brexit storm after previously suggesting the UK should rejoin the EU.
He confirmed that he thought leaving the EU had been 'damaging', but stressed he 'respected' the referendum result and was not pushing for re-entry to the bloc.
The comments came as he tries to fend off a Reform challenge in the Brexit-backing Makerfield constituency. Previously Mr Burnham called for the restoration of ties with Brussels 'in my lifetime'.
Giving a speech to a Northern investment summit, he also hit out at 'neoliberalism' and 'trickle-down' economics, complaining that wealth had been 'siphoned off' from workers.
Mr Burnham indicated that the North would get more funding at the expense of the South, arguing that the reverse had been true in a political system that had been failing for 40 years.