Pavel comes in for the suspended Steve Bywater against Derby and Crystal Palace, and says recent defeats on the road have hit hard.
"We have lost three really important away games because they were against teams that are really fighting for promotion - so those are the games you are fighting for six points, not three," he reasons.
"If you take the three it is really taking the six because it is like double points.
"But there is still a lot to play for and we have to believe we can do it - we have to go until the last minute of the season."
He acknowledges that West Ham SHOULD be in the top flight but warns:
"The history and the size of the club is there but sometimes in football when you go down it is really hard, because competition in this division is really tight - and there are eight or 10 teams that could get promoted.
"That is why it is so interesting and it makes things hard.
"The biggest problem for us has been drawing so many games and if two or three some of them had been wins it would have changed the whole season."
"It is a big weekend and it is an opportunity for me; I am getting towards the end of my career and I want to make the most of it."
As to whether he will earn a new contract at Upton Park, he adds:
"It depends where we finish this season; there are no discussions yet and the biggest thing is that West Ham go to the Premiership - this is where everyone wants to be."
And comparisons with his previous club Portsmouth?
"They have more players who have played more Premier League games and have more experience as well, because Harry Redknapp brought in some players who had played in the Champions League and 400 or 500 games in the top flight - international players," says Pavel.
"I would say that is the difference because West Ham have a lot of young players."
He says that he did not have any lengthy discussion with Harry about coming to his former club, and explains:
"We never had the opportunity to talk about West Ham; it hadn't been in my mind to come here, and it was quite a sudden thing.
"I didn't know if I would come here because I wasn't sure if his time at the club finished in a good way."
As for his future in general, Pavel reveals:
"I would like to play another couple of years and we will see what happens after that."
He is enjoying working with goalkeeping coach Ludek Miklosko - a fellow Czech, of course - and says:
"We can talk about things and share experiences; it is friendly and there is no pressure.
"The funny thing is that I speak to Ludo in English; Czech might be the first language in our heart but we speak English, which feels strange sometimes.
"But you want to be respectful to all the other players we are training with and the keepers we are working alongside."