Liverpool will take on West Brom on 17 May before finishing their season against Tottenham a week later.
"We have done our job. We have to keep winning, that's all we can do," added Benitez.
"It's a derby and if they make a mistake they will be feeling the pressure. Manchester City are a difficult team to play against.
"Clearly our position is very good, we have to keep pushing and wait - hopefully we can be top of the league next weekend."
Liverpool captain Steven Gerrard put Liverpool in front after just 76 seconds for his 22nd goal of the season, following up with a penalty rebound on 38 minutes before Ryan Babel's effort six minutes from time sealed a comfortable win.
"We're happy with the clean sheet, it puts more pressure on Manchester United," said Gerrard.
"They have a tough game against Manchester City, who have come into form recently, and it's a derby match, which are never easy. We hope Manchester City can do us a favour.
"When you come to tough places like West Ham, it's important to go in front and we did that. Looking at the game, we deserved to win."
Gerrard saw his 38th-minute penalty saved by Robert Green, only to tap in the rebound past the outstretched dive of the Hammers goalkeeper.
Gerrard 'proud' of Liverpool progress
And the midfielder admitted a morning conversation with Jamie Carragher had put the curse on his miss.
"He said to me this morning, 'You haven't missed a penalty for a while', so he's getting the blame," joked Gerrard.
"The win shows we are a good team and have a winning mentality. We deserve to be on top of the league."
Meanwhile, Hammers boss Gianfranco Zola said the 3-0 scoreline was somewhat harsh on his team.
"I don't think on the pitch there was a big difference," he said.
"In the first half we probably played better than them, the quality of the passing was good."
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