It had been a frustrating afternoon for long periods as West Ham’s resolute defending and brave blocking prevented a breakthrough. Neither side had a shot on target in the opening hour, with opportunities thereafter spurned from open play and the penalty spot when Jorginho’s effort was saved by Lukasz Fabianski.

Yet Thomas Tuchel’s men kept on pushing and their belief paid off late on as we found a way through when Pulisic arrowed a neat finish into the bottom corner to convert Marcos Alonso’s cutback cross and send Stamford Bridge wild with relieved joy.

It was our first home victory since a similarly dramatic late winner from Kai Havertz against Newcastle United in early March and the three points cemented our position in the Premier League’s top three, five points clear of Arsenal.

The selection

There were four changes for the Blues for the latest of our London derbies as Thiago Silva, Trevoh Chalobah, Jorginho and Kai Havertz all returned to the starting line-up.

Chalobah was a late replacement for Andreas Christensen from the team sheet originally submitted an hour prior to kick-off. That meant a reshuffle at the back with captain Cesar Azpilicueta to the left of Thiago Silva and Ruben Loftus-Cheek at right wing-back.

West Ham made six alterations of their own from last weekend’s draw with Burnley as Declan Rice, Jarrod Bowen and Michael Antonio all dropped to the bench. Arthur Masuaku, who scored the winner when the two sides last met in December, was one of those coming into the side.

Slow-burning start

In the sunshine of springtime in south-west London, this meeting of third and seventh in the Premier League had the two sides separated by 10 points at the start of proceedings, with both also competing for silverware on the domestic and European front.

West Ham’s Europa League semi-final against Frankfurt next week was perhaps on David Moyes’s mind with his team selection, the fact that winning that competition comes with an automatic place in next season’s Champions League also surely a key consideration.

The Blues, meanwhile, were keen for a return to winning ways after recent home humblings at the hands of Arsenal and Brentford, the need to improve our home form from the ninth-best in the league a pressing concern for Tuchel and his players.

Our positive start saw N’Golo Kante get the first sight at goal after Loftus-Cheek had snatched possession from Masuaku down the right. The Londoner pulled it back invitingly for the Frenchman but his left-footed effort dragged harmlessly wide beyond the far post.

Stalemate in the sun

Further endeavours came and passed. Timo Werner picked up the ball on the left touchline and drifted infield before floating in a delivery towards strike partner Havertz, though the ball was just too high for his compatriot to reach in the air.

Down the other end, Said Benrahma pounced to penalise Azpilicueta in possession but lacked support in the quick break forward and his low strike across the face of goal was easily handled by the falling Edouard Mendy.

Chalobah then had to be alert to intercept a teasing cross from Aaron Cresswell, resulting in the visitors’ first corner of the afternoon. Loftus-Cheek headed clear the danger and Alonso got his head in the way to block Masuaku’s volley before Mendy plucked the ball from the air.

Even half

The world champions came into this contest with 10 wins and four draws from our past 15 Premier League encounters with the Irons at home, though an uptick in intensity was required to break a lethargic start from both sides.

Mason Mount has been in prolific goalscoring form of late but the England international’s range was awry when he took aim for the first time 26 minutes into the contest, driving the ball over the bar with a left-footed attempt from just outside the box.

Azpilicueta saw an effort blocked after more good play down the right by Loftus-Cheek, while Andriy Yarmolenko had the half’s best chance 12 minutes before half-time when he escaped in behind the Blues backline to collect a pass from Pablo Fornals.

However, the Ukrainian’s hooked effort spun just beyond Mendy’s far upright and replays indicated the striker may have been fractionally offside anyway. The half ended with the hosts repelling West Ham’s familiar set-piece threat as Havertz headed away and the whistle sounded shortly afterwards, with neither side having registered a first-half shot on target.

Post-interval improvement

There was an immediate improvement in intent and intensity as Chelsea returned for the second half, which was swiftly mirrored by a rise in the decibel level from the home supporters, who roared in approval at two particularly crunching tackles from Loftus-Cheek on the right wing.

Werner had the best of our early flurry of openings, latching onto Loftus-Cheek’s headed knockdown to volley goalwards but thwarted by Craig Dawson’s impressive diving block. The centre-back was at it again moments later to get in the way of Kante’s strike from 20 yards out, the ball spinning up but failing to deceive Fabianski, who quickly adjusted to catch as he dived.

That was the game’s first effort on goal just before the hour mark, with West Ham having gone close to getting one of their own minutes before when Yarmolenko advanced down the right to tee up Tomas Soucek. A combination of Thiago Silva and Chalobah made the necessary intervention to prevent Mendy being worked.

Dawson denies Blues

Fabianski was called into more pressing action when Chalobah made inroads further forward, advancing in a similar fashion to the manner in which he scored that memorable goal against Crystal Palace at the start of the season. The young defender’s strike was crisp but West Ham’s Pole in the goal dived smartly to his left to palm the effort away to safety.

Yarmolenko then forced Mendy into a double save down low from close range but again would have been penalised for straying beyond the last defender too early. However, as the Blues dominated the ball and upped their control of the contest, the Hammers’ threat on the break also became more pertinent.

Nevertheless, Tuchel urged his charges forward in search of a winner and it almost arrived 20 minutes from time when Loftus-Cheek got in down the right on the overlap once more. Mount smashed the loose ball and it was destined for the bottom corner until Dawson produced an unlikely block, not for the first time in the match.

Frustrations grow

The Blues were growing frustrated as West Ham’s resistance stood firm, with Alonso’s header dropping onto the roof of the net before Werner’s final chance of the afternoon came shortly before his withdrawal.

A left-sided corner was cleared only as far as Alonso and the Spaniard’s delivery dropped nicely into the German’s path, though he was off-balance and could only slice his stabbed effort into the grateful gloves of Fabianski from seven yards.

Tuchel soon responded with a triple attacking change as Hakim Ziyech, Pulisic and Lukaku were sent on, the latter taking less than 10 minutes to make a significant impact when he won a penalty for the hosts.

Penalty chance

Thiago Silva provided the assist, rising high to flick on a clever header for the Belgian to run onto and Dawson was adjudged to have pulled the striker back as he tried to reach the ball before Fabianski. Referee Michael Oliver even upgraded his initial booking to a red card for the denial of a goalscoring opportunity, compounding the pain inflicted on the Hammers.

Jorginho stepped up in a battle of wits with Fabianski and the goalkeeper came out on top, refusing to move until the midfielder had struck the ball and then diving right to smother the attempt.

However, those thinking that was the last of the drama were mistaken as another substitute made the game’s telling impact. Ziyech whistled a firm shot just off-target but it was Pulisic who proved the match-winner in the final minute of normal time.

Mount punched the ball out left to Alonso and the wing-back took a look in the middle to see Pulisic holding back just outside the box. The assist was perfect, delivered low and with the right weight for the American to strike first time, left-footed and with unerring accuracy into the bottom corner.

At the end of a game lacking in that crucial penalty-box composure and class, one moment of poise from Pulisic proved the difference, taking the Blues seven points clear of fifth place with a game in hand.

What’s next?

Our Premier League campaign moves closer to its conclusion with a trip to Manchester United on Thursday night before we travel to Everton three days later.

Chelsea (3-4-1-2) Mendy; Chalobah, Thiago Silva, Azpilicueta (c); Loftus-Cheek (Ziyech 76), Kante, Jorginho, Alonso; Mount; Havertz (Lukaku 76), Werner (Pulisic 76)Unused subs Kepa, Sarr, Saul, Barkley, KenedyScorer Pulisic 90

West Ham (3-4-3) Fabianski; Johnson, Dawson, Cresswell; Coufal, Soucek, Noble (c) (Rice 62), Masuaka; Yarmolenko (Bowen 73), Fornals, Benrahma (Lanzini 78)Unused subs Areola, Alese, Fredericks, Kral, Vlasic, AntonioSent off Dawson 86

Referee Michael OliverCrowd 32,231