CONOR O'Shea admitted Harlequins were not at their best in beating Northampton to reach the Premiership play-off final on Saturday.
Quins left it late against the Saints, trailing by eight points going into the last eight minutes before a Nick Evans penalty and a Joe Marler try, converted by Evans, snatched victory from the jaws of defeat.
All of which sets up a final showdown with Leciester on Saturday week, and director of rugby O'Shea admits his side will have to put in a better show against the Tigers.
He said: “The occasion looked like it got to us. We got ourselves in plenty of positions to win it, but kept letting them back into it.
“We didn't play that well, but semi-finals are only about winning. The belief is unbelievable, but we have done nothing yet - and we will have to improve in the final."
Quins were left with an agonising wait while Marler's winning score went to the video ref before being confirmed, but O'Shea insists he knew the outcome all along.
He added: "There was no way that was going to be anything but a try unless the ball was knocked on during the move, but luckily nobody had done anything stupid."