The Potters face Chelsea at Stamford Bridge on Sunday in a game the Blues needs to win in the battle for the Premier League title.
Pulis said: “We can upset them. We will give it our best show and we have nothing to lose. All the pressure will be on Chelsea.
“I’m not sure we will enjoy it, but we know we can work hard and give it the best we can.
“But you are always concerned against the top four or five clubs, if they are firing right you can end up with your pants pulled down and your backsides really slapped. But we aim to give it our best shot.
“We have been close to them without taking any points off them. We know we are capable of causing an upset.”
He added: “We can almost touch 46 points now, it is very important that we overtake last season’s tally of 45, and to maintain our position in the top half. That shows progress.
“If we can get to that mark it will be a cracking season for us, better than the last one and showing we have got better.
“I certainly wanted to get to that stage in points won, or close, before we faced the last few games at Chelsea and Manchester United and at home to Everton, as well as a visit to Fulham.
“They were always going to be tough games. Everton are a very well organised side with their injured players back now, while going to Stamford Bridge and Old Trafford will see us facing one of the sides who will be the champions.
“If Chelsea don’t do it then it will be Manchester United. That is a tough end to a season for anyone and we are aware of the challenge.”
