"He is a big danger because he is a counter-attacking player and away from home their game is based on him," Wenger told Arsenal TV on Tuesday.

The Arsenal boss believes that Ronald Koeman's team are likely to play a more defensive game, trying to hit on the break through the pacey Farfan.

"PSV are a cautious team who came out in the first game and beat us on the break," said Wenger at the weekend.

"They try to suck you in and counter-attack."

Meanwhile, Wenger revealed that Arsenal skipper Thierry Henry is fully fit to take part in the crucial game.

The French striker was doubtful due to a foot problem but Wenger assured that he is ready to help the team overcome the 1-0 away defeat after taking part in the team's training on Tuesday.

"He can play because he played this morning. He can start if I decide to start him," the French tactician told Sky Sports.