Frank Lampard scored his 200th career goal for Chelsea to help them to a 2-0 victory over the Hammers at Stamford Bridge, with the impressive Eden Hazard grabbing their second.
The triumph came after they turned around their UEFA Europa League tie with Steaua Bucharest in midweek to advance to the quarter-finals and Benitez is pleased to see his side on the up.
He told Sky Sports: "It's a pity because it was a great win, a great result for us, a clean sheet, two goals, 200 goals for Lampard, but we could have maybe scored three or four goals and it would have been even better.
"West Ham are a difficult team to play against. Free-kicks and corners are always a problem. If they'd have scored one goal they would have been back in the game so we needed to score the third goal, kill the game, but we didn't do it.
"We're still very positive. The week was very positive for us and today the team was playing great football."
On Lampard reaching his milestone the manager added: "He's a great player. 200 goals for any player is a fantastic achievement. For a midfielder it's even better.
"He could have scored one or two more goals. I'm really pleased for the team, really pleased for him and for everyone here."
David Luiz was substituted for John Terry in the 78th minute with an apparent injury and Benitez says he does not yet know the severity of the damage.
"We don't know. We need to talk with the doctor because we don't know how serious the problem is," he said.
"We made the substitution just in case but we need to talk with the doctor."