West Ham’s goalkeeper, David Martin, embraced his father Alvin after an emotional Premier League debut at the age of 33 – and revealed he could hardly eat for two days in the build-up.

The former Millwall and MK Dons keeper pulled off a clean sheet on his top-flight debut as West Ham secured a surprise 1-0 victory at Stamford Bridge, with his dad, the former Hammers stalwart, watching from the stands.

Martin, who replaced Roberto in goal, said he was in tears as he walked into the crowd to hug Alvin, the former England defender who spent 20 years at West Ham between 1976 and 1996.

“It just doesn’t feel real,” he said afterwards. “I’m 33 now, I’ve had a decent career, I’ve played quite a few games but it still doesn’t prepare you coming into this. I’ve been struggling to eat for the last two days. Cress [Aaron Cresswell] was laughing at me because my plate kept being taken away and I couldn’t finish my food.

“When I saw my dad we were both in tears, so we didn’t actually say a lot. But for my dad to see that here with the club he played for for 21 years, to make my debut, keep a clean sheet and get the win for the boys more importantly, it’s just a fantastic feeling.”

David Martin hugs his dad Alvin after the final whistle. Photograph: Dave Shopland/BPI/Shutterstock

Manuel Pellegrini admitted he was relieved that a series of changes had paid off as his team ended an eight-match winless streak in all competitions. The Chilean’s job remains on the line but he felt the result could be a turning point.

“When you don’t win you are a beast and when you do you are a genius,” said Pellegrini. “For the team, for West Ham, for me and everyone, I think they did very well. But not only because I changed the goalkeeper. I think everyone produced the intensity you needed to win the game.”

Praising Martin’s debut, he said: “Of course, we know his family is linked with this club. It was not easy for him to make his first Premier League start. But I think that from the first time I spoke in the week with him I felt he was prepared. Before the game he was very quiet but he demonstrated what he needed throughout the 95 minutes.”

Aaron Cresswell’s neat finish sealed West Ham’s win, prompting a frustrated Frank Lampard to challenge his Chelsea side to produce a quick reaction in defeat.

“Shocked isn’t the word, I’m more disappointed,” said Lampard. “We didn’t perform the way we wanted to. But I do believe in the squad. There haven’t been many times I have said we were below par but today was one of those days. I don’t think it’s time for harsh reactions and judgments. It is time for a look at a bit of character to see our reaction.”