Roy Keane believes Manchester United are still "a few years" away from winning another major trophy.
After a disastrous campaign under David Moyes, Louis van Gaal has been tasked with getting the club back into the Champions League and was supported by six new first-team signings this summer.
United sit fourth in the Premier League with 11 points but Keane, who won 13 trophies during his 12-and-a-half years at Old Trafford, predicts a title challenge will be difficult.
"It's been a bit better these last few weeks," Keane said in an interview with BBC's 'Football Focus'.
"Clearly they are going to win lots of football matches because they've got lots of goals in their team now. Going forward, the players they have available - amazing.
"But, in terms of winning the bigger prizes again - the Premier League and Champions League - I think that might be a few years down the road yet. Only in a sense that defensively they look to rebuild.
"You can win football matches going forward, with lots of goals, but I think at the back with the lack of experience, and injuries problems at the moment, it will be very hard to win titles."
