West Ham United defender James Collins has said that Astra Giurgiu will not be easy opponents when they meet in the Europa League third qualifying round on Thursday.

Slaven Bilic's side almost suffered a huge shock last week when Maltese minnows Birkirkara forced them to a penalty shootout in the second qualifying round, and Collins is refusing to underestimate the Hammers' next tie.

"We've had a couple of tough games already and the game on Thursday is not going to be a walkover," he told the club's official website.

"They are a good side we are playing against, and it's good preparation for us to know the gaffer, and for the gaffer to get to know us as players and see us play.

"As players we've used these games to impose ourselves on the new staff, and tomorrow night we have a good chance of doing that."

West Ham are unbeaten in pre-season friendlies since last week's shaky meeting with Birkirkara, drawing against Charlton Athletic and picking up a 1-0 win away to Norwich.