The veteran struck in the 2-0 triumph.
"It's my first goal in a West Ham shirt, which is something special," the No5 said. "It took me two years, but it was a great performance by the whole team.
"I had the chance to win this competition with Manchester City, and I know it's very special. We haven't been great in the FA Cup in the last few seasons, but today was a good performance and we played with the respect that this competition deserves.
"We're taking the FA Cup seriously, we have a great squad, great players, so I'm pleased for the team today."