Darren Fletcher says Manchester United will target Cesc Fabregas for rough treatment.

The Arsenal captain has returned from a near four-month absence with knee ligament damage in sparkling form, including scoring both goals in last weekend's 2-0 win over Middlesbrough.

Recent matches between the two sides have seen a cessation in the hostilities of past years but Fletcher has turned up the heat ahead of the semi-final first-leg tie by urging United to test Fabregas and his team-mates' hunger for the fight.

He said: "Fabregas is a top-class player. You expect to come up against players like that at this level but you can't show them too much respect.

"You've got to see if they're ready for a battle, if they fancy it and we'll definitely take the game to them. If we win more individual battles, then we should come out on top."

Meanwhile, Arsenal's Mexican striker Carlos Vela was at the centre of a swine flu alert yesterday.

Vela was ordered to stay away from the training ground amid fears friends from his home country, who visited him at the club's training ground last week, had contracted the disease.

Vela was allowed to travel with the rest of the squad after being given the all-clear last night.