Astra Giurgiu manager Marius Sumudica is wary of a West Ham United side evolving under their new manager Slaven Bilic ahead of Thursday's UEFA Europa League meeting at the Boleyn Ground.
Sumudica was an interested observer as the Hammers took on Norwich City on Tuesday and the 44-year-old admitted to being impressed with they way they ended their 1-0 victory.
Having seen off Inverness Caledonian Thistle in the last round and reached the group stage of this competition last year, Sumudica believes his team possess the ability to cause the Londoners a headache but knows Astra will have to be at their best.
"This is a very important match for us," he said. "It's the first leg, so the first battle to win the war and I'm sure it will be difficult.
"The crowd will try to make our lives very hard, but we are ready to fight here and we will give everything.
"I watched West Ham's game against Norwich on Tuesday, and I watched the games against Lusitans and Birkirkara too.
"They left a very good impression, the team has changed under the new manager and I can say they play a different type of football to the other English teams.
"They have a high pressing line and they try to play football. We will have to be very careful, and watching the last half hour against Norwich, the nine players they brought on, who I think will start against us on Thursday, have a very high quality.
"We have to fight our enthusiasm, because we had an away win at the weekend, so it's human to be in a state of enthusiasm after that.
"We have to be careful that we're not over-confident so we have to focue and concentrate very well."
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