Brett Holman believes AZ Alkmaar must attack to have any hope of maintaining their interest in the Champions League.

Ronald Koeman's men face a must-win clash against Olympiacos at the AZ Stadium on Tuesday night.

Qualification for the knockout phase is a tall order with AZ bottom of Group H and having collected just two points from four games, but Holman is not giving up hope.

"I expect a tough game," said the 25-year-old.

"Olympiacos are a good team. They are tactically well skilled and their defence is very well organised.

"We enjoyed the bulk of possession when we met them on matchday one, but we created few chances.

"We should create more chances, in particular when we play at home, in order to secure a victory."

The size of the task is also not lost on Koeman.

AZ were beaten 4-1 at group leaders Arsenal in their last outing in the competition but go into the game buoyed by a 4-2 win at Roda in the Eredivisie last weekend.

Koeman, the former Ajax and PSV Eindhoven boss, said: "For me, the story is simple.

"Tomorrow night's game is a must-win game. Only a win will put us back into contention for the qualifying places in Group H.

"I don't think Olympiacos will make the trip to Alkmaar just to lay on attractive football to thrill and entertain the crowd.

"Olympiacos are set to opt for a defensive approach.

"I think the reverse tie in Greece was an easier challenge for us.

"Olympiacos will look to keep it tight against us."

The Greeks won 1-0 with a late Vassilis Torosidis goal when the sides met in Piraeus in September and have since picked up another win over Standard Liege.

Zico's side are well placed in second in the group but, having also lost twice in the competition, including a reverse to the Belgians, their qualification is far from secure.

Their task on Tuesday is a testing one on paper with AZ having lost just once in 35 home matches in European competition.

And Koeman is also backing goalkeeper Sergio Romero to make life difficult for the visitors.

The 22-year-old Argentina international is under pressure after a number of recent errors but Koeman is confident he will deliver.

Koeman said: "Sergio Romero is our man between the sticks against Olympiacos.

"Whether this is his final chance? Well, I actually don't know about that, but I told him he should improve.

"I think he's got the message, he was terrific at training.

"He is still a young lad and of course he is not perfect.

"Sergio Romero can cope with pressure. The pressure on the national team of Argentina is far higher than here in Holland."