David Moyes may well be glad that he put all his eggs in the Europa League basket after Christian Pulisic’s 90th-minute winner.
His second string had fought so hard for so long only to be undone in the final minutes here.
Amid a defensive crisis and with Thursday’s Europa League semi-final looming, Moyes said this week that he was facing a juggling act to put a side out here.
Having agonised over how to strike a balance, Moyes fell in favour of making Thursday a priority and left Declan Rice, Michail Antonio, Jarrod Bowen and Manuel Lanzini on the bench.
A switch to a makeshift back three helped cover the absence of Kurt Zouma and Issa Diop, with full-backs Ben Johnson and Aaron Cresswell flanking Craig Dawson.
With Mark Noble and Tomas Soucek ahead of the back line, West Ham frustrated Chelsea throughout a flat first half in which the closest Thomas Tuchel’s side came was a low effort from N’Golo Kante which rolled wide of the post after just eight minutes.
Chelsea turned up the pressure after the break, with Dawson twice throwing himself in front of strikes from Timo Werner before getting something on Kante’s effort. Trevoh Chalobah resorted to an effort from range which Lukasz Fabianski matched with a diving effort.
With an hour gone and the scores level, Moyes began calling for the cavalry. First Rice replaced Noble in midfield before - ten minutes later - Jarrod Bowen was sent on in place of Andriy Yarmolenko, who had just forced a double save from Edouard Mendy at the near post.
West Ham were growing in belief they could get something, especially with Dawson blocking another effort - this time from Mason Mount.
Cresswell then put himself between Kante’s effort and the goal as the frustration forced Tuchel into a triple change. Pulisic, Hakim Ziyech and Romelu Lukaku - more than £190million worth of attacking talent - were sent on to find a way past £2m Dawson, and it worked.
After a superb display, Dawson finally cracked.
The 31-year-old resorted to pulling back Lukaku’s arm on the edge of the penalty box. Michael Oliver pointed to the spot and, after being sent to the monitor for a review, showed the defender a red card.
Fabianski made one of the easier saves of his career to keep out a poor penalty from Jorginho, looking to have secured a point West Ham were more than worthy of.
But with a man advantage - Chelsea finally found a way through.
Rice had dropped back into defence to cover for Dawson, leaving a pocket in midfield which Pulisic was only too happy to exploit as he met Marcos Alonso’s low cross to fire home first time.
In truth, Moyes will not care a jot if his decision to rest his key men pays off against Frankfurt this coming Thursday.
But with West Ham still outside the top six with just four games to go it is becoming increasingly important that it does just that.
