"It is not do or die because there are a number of games afterwards but you certainly can't overstate the importance of the game in the context of the season and the club," he says.
"It is a massive game and it will be a huge boost if we win, as well as causing a stir everywhere else.
"It is a game we dare not lose. Both teams have been on a good run of late and it is going to be tough - and an exciting afternoon.
"I think when you look at the fixtures you look at this and likewise the Birmingham on the last day of the season and you think 'hang on, it may come to that - it is of ultra importance'."
Paul reveals that Michael Carrick remains a doubt for the Hammers, echoing Glenn Roeder's point that the club has to be cautious about risking him if he is not fully fit.
"Michael is working hard on his own with the physios," says Paul, "and as the week goes on I am sure he will try to join in with the boys; we will have to wait and see.
"It is such an important game coming up and we are not taking any chances; he must be 100% if he is to play."
Looking back on Saturday's draw with Aston Villa, he says: "It was a game in which we created so many chances to win and we played the good football to create them - but if you don't take all your chances as happened on Saturday you risk not taking the three points, which is what happened.
"Every game that goes by it makes it tougher when you don't win and those two points dropped have gone."
But Paul also points out that justice was not done at the weekend, especially with regard to the penalty incident against Tomas Repka.
"The first goal is a controversial decision by the referee. None of their team even appealed and you probably get about 20 of those sorts of clashes in a game where nothing is given," he insists.
"The striker was backing in and Tomas just got his head to it. Everyone, even their bench, was surprised when he gave the decision and pointed to the spot.
"Unfortunately this referee seems to be having a good old spell of giving controversial things against us.
"I think you can tell by the players' reaction in the immediate vicinity and the Aston Villa players were as surprised as anyone; it was just a collision, but we have to get on with it.
"Referees' decisions are crucial whether they go for or against you and that is why you try to get professional referees who understand the game and you hope they make as many good decisions as a human being possibly can.
"The second was even more disappointing; we were slow out of the blocks in the second half, it was slack defending, and there was a five minute spell when we were second to the ball.
"But credit to Villa, in that time they had us on the rack and created a few chances themselves.
"After that, though, the boys were superb and after Fredi's equaliser they did everything bar score again - we thoroughly deserved to win and even Graham Taylor said that to us afterwards.
"But their keeper made some stunning saves which, as a professional person, I can admire because they were top quality.
"But he made two or three that were very lucky as well, and it is a very fine line."
As for the players' reaction, he adds: "They were all disappointed in the dressing room on Saturday and it was quite strange in the dressing room because there was the realisation that we had played some great stuff which, on another day, would have seen us easily get five goals.
"That has to be our spur - if we were playing poorly and not creating chances then we would all be really worried - that is not the case but the situation is now coming to a climax."
Meanwhile, Paul is laughing off a report that, to use the phrase of a newspaper, the season has been 'rocked' by what was claimed to be an 'outburst' by Paolo Di Canio in training.
That is not disrespectful to Paolo, merely an illustration of the contempt he has for the story, and he says: "It was absolutely nothing and it is not worth talking about. On the training ground, myself, Glenn, or Roger are coaching as well as refereeing and decisions are given which players are upset about - there is nothing to it.
"The boys have trained absolutely superbly this week - but they have done for a long period of time."