The Hammers missed the chance to regain a top six spot in the Premier League after slipping to a 3-1 loss against Spurs, but Tomkins does not want this result to upset team morale following their fine early season form.
Leaders Manchester United are next up for the east Londoners on Wednesday and the defender admits the players must approach this match with the confidence of a high flying side if they are going to pull off a result.
He said: "We didn't play at our best but we need to put it behind us quite quickly because we have another big game at Manchester United in a couple of days' time and the games are coming thick and fast.
"We don't need to dwell on the result because we have the points on the board and it's vital we go to Old Trafford with our confidence intact.
"We have to make sure we go to Manchester United 100% mentally."