Man Utd's Sesko strikes late to rescue West Ham draw
Trailing to Tomas Soucek's second half goal at the London Stadium, Carrick was seconds away from his first defeat in five matches before Sesko struck at the death.
Carrick had revitalised United with wins over Manchester City, Arsenal, Fulham and Tottenham since replacing the sacked Ruben Amorim.
The former United midfielder is only in charge until the end of the season, but his flying start has seen him tipped to win the job on a permanent basis.
This disjointed display was the least impressive of his brief reign, but Carrick will take heart from the way his players refused to accept defeat.
United held onto fourth place in the Premier League, one point ahead of fifth-placed Chelsea in the race to qualify for the Champions League.
Third-bottom West Ham's failure to hold onto the lead left them two points behind fourth-bottom Nottingham Forest in the relegation battle.
Forest play their game in hand against bottom of the table Wolves on Wednesday.
United fan Frank Ilett was denied his long-awaited haircut by the draw.
Ilett has racked up more than two million social media followers since pledging in October 2024 to grow his hair until United secured five victories in a row.
Now he will have to hope United embark on another winning streak before he can get the scissors out.
West Ham forward Crysencio Summerville had five goals in his previous five games and he almost made it six with a stinging strike that Senne Lammens pushed away at full stretch.
United struggled to find any rhythm for long periods of the first half.
They created a rare threat from Bruno Fernandes' corner, with Luke Shaw's close-range effort cleared off the line by Aaron Wan-Bissaka.
United's forwards were starved of service and when Amad Diallo had a sight of goal, he fired into the side-netting from an acute angle just before the interval.
Carrick's men paid for their lethargy five minutes into the second half.
Unable to trap West Ham with a high press, United were caught flat-footed by an incisive break.
Soucek picked out Jarrod Bowen on the right flank and made a perfectly timed run to meet the England forward's low cross with a flicked finish from five yards.
It was a sloppy goal to concede, with Shaw and Kobbie Mainoo both guilty of slow reactions as the move gathered steam.
United were denied a 63rd minute equaliser after Casemiro's header was ruled out for offside following a VAR review.
Carrick's side dominated the closing stages but it appeared their final chance had gone when Joshua Zirkzee headed inches wide from close-range in stoppage-time.
However, there was a sting in the tale for West Ham as Sesko levelled with just seconds left.
Bryan Mbeumo swung in a teasing cross and Sesko deftly guided his finish past West Ham keeper Mads Hermansen from 10 yards.