The manager told reporters: "I've sensed the joy and the goodwill feeling around the camp. There's a buzz around training which is always good to see. But the players now need to maintain and build on their performances.
"We need to make sure we are mentally prepared for the game against Stoke City. It's very easy to lose after a big result like the one against Manchester City, so I need to make sure the players are guarded against that.
"I think we're all surprised at how consistently good our performances have been so far this season and that has been very pleasing. We've had quite a number of injuries to deal with, but only one-and-a-half performances so far have been below my expectations in nine matches."
West Ham are currently fourth in the table, seven points behind leaders Chelsea.