LONDON, Oct 27 (Reuters) - Jarrod Bowen converted a controversial last-gasp penalty to lift West Ham United to a 2-1 Premier League victory over Manchester United ( MANU ) in a fluctuating clash between two struggling sides on Sunday.

Crysencio Summerville scored his first goal in a West Ham shirt as they climbed past their visitors to 13th in the table on 11 points after nine games, level with 14th-placed Manchester United ( MANU ).

Although Man United's loss was only their second in 10 matches across all competitions, it will put manager Erik ten Hag under pressure again.

"Three times this season we feel injustice," Ten Hag told the BBC. "We have to score, we created so many chances. We should've been two or three up.

"Second half we were forcing it but we allowed them into the game. When you are losing 1-0 you need big personality and character of the team and showed resilience to get back into it. Unfair and unjust the way we conceded the penalty."

Bowen netted in the 92nd minute, stepping up to the penalty spot after a lengthy VAR review showed Matthijs de Ligt had clipped the leg of Danny Ings, a decision that left Ten Hag shaking his head.

"I spoke with (the officials)," Ten Hag said. "But the decision is made. There's no way back and that's football."

Bowen launched a low penalty just inside the post, beyond the hands of Andre Onana who dived the right way.

West Ham were fortunate not to concede in a first half dominated by their northern rivals and were much brighter in the second after manager Julen Lopetegui brought on Summerville and Tomas Soucek.

"Happy for the three points. We are happy for the fans and players, they deserve this victory after suffering a lot in the first half," Lopetegui said.

"Second half we changed different things and the first half was for them but the second was for us. We were able to compete better and win the match."

Summerville got them on the scoreboard in the 74th minute when he slid in at full stretch to poke home Danny Ings' scuffed shot.

Seven minutes later, Casemiro silenced the home fans when Diogo Dalot headed across goal from a cross, Joshua Zirkzee helped it on, and the Brazilian midfielder nodded home at the back post.

The travelling supporters' celebrations were short-lived, however, and after 12 minutes of added time they were left to rue another loss.

Ten Hag's team will regret their opportunities squandered, particularly in the first half starting with a long shot inside two minutes that Alejandro Garnacho rattled off the crossbar.

"We have to look in the mirror, we don't score in a good game from our side," Ten Hag said.

Hammers keeper Lukasz Fabianski made a terrific save in first-half stoppage time, stretching to get his fingertips on Casemiro's header from Christian Eriksen's free kick.

West Ham had a narrow miss early in the second half when Michail Antonio sprinted towards goal with Onana rushing out to stop him, the keeper suffering a blow to the head in the process. Onana was down receiving medical attention for several minutes before play resumed.