The Hammers players have been the subject of niggling and abuse from FC Lusitanos and Birkirkara FC in their opening two rounds of qualifying for Europe's seconed tier club competition.
Diafra Sakho and James Tomkins have both seen red in the opening ties, assisted by the opposition players, but centre-back Collins wants the east Londoners to simply worry about playing football as they prepare for Thursday night's clash with Romanian club Astra Giurgiu.
"Some of the stuff that was going on on the pitch [against Birkirkara] was unbelievable," the 31-year-old Welshman said.
"They got under our skin. Everyone could see that. It worked.
"They spoke about doing it before the game and from minute one they tried everything they could.
"They were doing everything they could to get underneath our skin, which obviously they did which didn't help the situation.
"These teams are coming to play us, looking at it as a cup final so they will try anything they can to beat us. We have to be streetwise to that, deal with that and let our football do the talking.
"But that is what they are going to try to do. They are going to try everything to get an upper hand on us.
"James Tomkins was sent off in the last game and Sakho in the game before. That can't happen.
"We need to be more streetwise."