"When Arnautovic was injured, I called him because he was making his warm-up, but when he was back sitting on the bench and Antonio was working I called him because he was ready". When Marko had a problem with his knee, I wanted to put Lucas on.
West Ham were at it again in the second half and found their third goal on the hour mark when Pedro Obiang played Marko Arnautovic into space inside the box and he duly fired past the keeper to make it 3-1. "And when you get a performance like that as well, it gives you a lot of belief".
He said: "I was not anxious about my birthday today - I just wanted to win the game - it was the best gift my players could give me".
'Given the false information spread by the media that has affected my image, I am obliged to explain the only truth: I have never ever refused to warm up in my whole career, let alone play in a match, ' Perez posted on Twitter. It's not good to start with some bad results, but we are absolutely confident that we're going to reverse it.More news: Iran OPEC chief: 'Saudi and Russian Federation are taking oil market hostage'
Victory will go a long way to alleviating frustrations in east London after the club lost their opening four matches, and Pellegrini now believes the club can still achieve their objectives this season after the poor start.
Yarmolenko, who joined West Ham from Borussia Dortmund in July, opened the scoring in the 11th minute.
Perez has not seen many minutes for West Ham this season, appearing twice off the bench in the Premier League.
And Hammers captain Mark Noble added: "The table looks a bit better now after our first three points". Sometimes that's what you need, and since then we've had two hard weeks of training.