Cardiff, still without an away win this season, blew a golden chance to take the lead when Joe Ralls saw a first-half penalty saved by Lukasz Fabianski.

And substitute Perez made up for the loss of top scorer Marko Arnautovic to a hamstring injury with a quickfire double at the start of the second half.

"I think it was a strange game," said Hammers boss Pellegrini. "We started very well, we had clear chances to score, but after that we didn't make good movement and Cardiff had some shots.

"The penalty was absolutely unnecessary, fortunately Lukasz saved it.

"When we scored the first goal it relieved the pressure, we played with more freedom and that helped us score the other two goals.

"Cardiff are a difficult team, they work very well in the way they like to play.

"Lucas' goals were very important for the team. After that, for different reasons Lucas didn't start so often but it is important that when the player has the chance, he takes it."

Arnautovic's injury will be assessed on Wednesday, while Pellegrini also revealed Jack Wilshere was not in the squad due to a problem in his ankle – although not the same one that has sidelined him for much of this season.

Cardiff boss Neil Warnock admitted the penalty miss was crucial.

Referee Graham Scott pointed to the spot after Arnautovic shoved Junior Hoilett in the area but Ralls could not take advantage, and with it went Cardiff's chance of a first away win of the season.

Nevertheless, Warnock said: "I thought it showed we could win games away from home tonight.

"I said to Manuel in the technical area 'how can we be losing?' If the penalty goes in you could just sense the crowd felt it wouldn't go their way. But it takes guts to take a penalty – I wouldn't even watch one.

"We looked a decent side, we played some good stuff and it would have been interesting to see the penalty go in."

Josh Murphy headed in a scrappy consolation goal for Cardiff in stoppage time.

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