Manchester United boss Sir Alex Ferguson praises Nani's 'fantastic talent' but will be worried by Phil Jones injury

United beat Reading 2-1 to progress in the FA Cup

Sir Alex Ferguson admitted last night that Luis Nani had left him with a selection headache after his exquisite performance sent Manchester United into the FA Cup quarter-finals and on course to meet Rafael Benitez's Chelsea.

Nani's troubled season in Manchester was compounded by a collision with an unmarked police car in south Manchester last Friday night, which left him uninjured. But the 26-year-old winger could reflect on a performance which may encourage Ferguson to go to new lengths to persuade him to sign a new deal replacing the current contract which expires in the summer of next year.

"He has got great talent, we know about that," Ferguson said of Nani. "He is a fantastic talent. I had a feeling he would win the game for us. You could see he was right on form when he came on: two great strikes immediately and he was a threat to them after that all night. It is a good addition. If he keeps that form it makes my job more difficult." Nani said: "I'm so happy for the time [on the pitch] and I will keep working."

But the gloss was taken off Ferguson's night by an ankle injury which saw Phil Jones substituted before half time and limping out of Old Trafford on crutches with his right foot in a cast. The manager said the ankle injury would be assessed today and that Jones would probably miss Saturday's visit to Queen's Park Rangers. But the player's availability for the home leg of United's Champions League tie with Real Madrid on 5 March is also in doubt – a blow, since he played a crucial role in quelling Cristiano Ronaldo's threat during the 1-1 draw in the Bernabeu last week.

Ferguson said his side had been profligate in front of goal, on a night when the Reading defence were at their best. "If you don't score the goals you should do, and then concede one, then the last 10 minutes can be scary," he said. "At 0-0 you have to be [worried]. They scored the goal and we didn't want the replay. You don't want that. But in fairness we dug in. We defended the long throw-ins into the box which a lot of teams do these days and just hoped they get the final touch. But we could have scored a lot of goals. In that sense, I am satisfied."

His opposite number, Brian McDermott, who hopes to have Noel Hunt available to face Wigan at home on Saturday despite needing staples to a head wound, justifiably argued that his side had no reason to feel they lacked ambition. "[I'm] not regretting anything. It's about having the opportunity to do it. They're a great team and manager who will probably win the league," he said. "Sir Alex was talking about the best squad he has ever had and I wouldn't argue with him. We were right in there right to the end. It was a proper performance for our fans. Now we move on to our next game."