Ahead of Sunday afternoon's match at London Stadium, the Colombia international said: “For us it is a very important game, like all of them, but we know we need to win. We haven't achieved that for two games.
“It has been difficult, but hey, this is the Premier League. Nothing is determined until it is played and there are always opportunities.
“We are preparing well. The team has recovered super quickly. We hope to win and we hope that everything works out perfectly.”
Following back-to-back defeats, the Eagles will come up against a West Ham side that have won their last three consecutive matches in all competitions.
Nevertheless, it is a Premier League fixture which has proven profitable for Palace in recent seasons, the south London team having gone unbeaten in their last four visits to east London, and having won both home and away against West Ham last season.
Lerma noted: “Well, it's no secret that they have good players. They are in a good moment too.
“I prepare like always: with enthusiasm and with the desire to win every duel. Since training, I’ve began to have those good feelings and know that I have to go for them to win each duel.
“These types of games are special because of what we play for. I think there is a strong rivalry because we are from the same area.
"I want to play [the match] and get the three points. I think it's a good opportunity [for us] to succeed.”