Former Manchester United midfielder Lee Sharpe believes that manager David Moyes's future at Old Trafford is still in doubt, despite guiding his team to the quarter-finals of the Champions League.

The Red Devils overcame a 2-0 deficit courtesy of a Robin van Persie hat-trick in last night's victory over Olympiacos on home turf.

After Sunday's humiliating 3-0 defeat to arch rivals Liverpool in the Premier League, there were suggestions that Moyes's time at United could be coming to a close.

While a positive atmosphere may ring around Old Trafford following last night's triumph, Sharpe believes that Moyes's future is not safe yet.

When asked by talkSPORT if Moyes will be at United next season, Sharpe said: "I'm not sure. If they've got £100m to spend on transfers, I'm not sure you are going to give it to him to spend."

United will take on West Ham United this weekend before facing local rivals Manchester City on the following Tuesday.