"I thought Trevor was very unlucky," says Paul. "Obviously the referees have decided to clamp down on the diving situation but I thought he was trying to go the long way round Lucas Neill - and he was going at pace as well.
"It is very easy in that circumstance to lose your footing. He didn't fling his arms up in the air and roll over looking for a penalty.
"It was deemed as a dive but it was very, very harsh.
"Graeme Souness was unhappy with the referee from the word go and by no means would I have classed that game as anything but fairly contested, and yet there were far too many bookings for the context of the game.
"The referees really do put pressure on themselves, or they have it put on them by the rules, but once they book someone early on that player could make a slight error of judgment later on and end up getting sent off.
"Both the boys are disappointed, Trevor and Sebastien, because they both miss the next round of the FA Cup if we get through or the league game against Middlesbrough.
"It is really disappointing when that happens - but it is a fact of life and we have to get on with it.
Meanwhile, Paul is calling on the side to frustrate what he regards as the best forward line in England.
He says: "In my opinion Chelsea have the best pairing of strikers in the whole league, and that is not taking anything away from the other top class strikers that other teams have got.
"They link up brilliantly well and they both dovetail each other with Gudjohnsen's trickery and Hasselbaink's power, pace, and goal scoring ability.
"They are a formidable partnership but they have players of great ability right throughout the team.
"A ready made player of Hasselbaink's stature would cost you multi millions."
He believes that the FA Cup is the best competition on the planet, and hopes that the Hammers can emulate the league win earlier in the season - one of Chelsea's rare defeats this campaign.
"I don't know how many league games they have lost this year but when we beat them it was their first of the season," he says.
"The cup game is a nice respite from the pressures of the league and we know it is going to be a very hard game because they have a fantastic squad.
"If you have got a small squad then suspensions and injuries can really affect you in the league, but it is a fantastic tournament, the best cup competition in the world, and it is everyone's dream to get to Wembley - or Cardiff rather!
"We are no different and we will be giving it everything we have got, but it is not easy to get to finals now because teams with bigger squads have a bit of an advantage, especially this time of the year when there are suspensions."
Of the defeat at Southampton and win at home to Blackburn, he says: "The disappointment at Southampton was felt by us all. We felt we were a little bit unlucky to lose it, but we were also disappointed at the way we couldn't respond after they got the goal, so Saturday was important.
"We played some very good football going forward, but they had a lot of possession and in the end we were playing a little bit on the counter attack.
"But I felt we always looked a little bit more dangerous than they did."