Jose Mourinho would have to be "like Dynamo the magician" to turn Manchester United into Premier League champions this season, Andy Cole has told BBC Radio Manchester.
Mourinho has started re-building a squad that finished fifth in the Premier League last season and missed out on Champions League qualification, with Eric Bailly, Zlatan Ibrahimovic and Henrikh Mkhitaryan already having signed.
However, former United striker Cole, who was part of United's Treble-winning side in 1998-99, thinks it might be a step too far to expect them to win the title at this stage.
"To sit here and say Man United are starting the season as favourites? I'm not sure about that, considering where they ended up last season," Cole said. "There will be some more players coming in but the Premier League gets tougher and tougher.
"If Jose Mourinho comes to Man United and wins [the Premier League] in the first season, I think that would be absolutely like Dynamo the magician. It would be fantastic. He's under no illusions how tough it's going to be to come to Man United and try to win the Premier League in the first season."
Several top clubs will be looking to fight for the title this season and, with Leicester's shock success last season, Cole said it is difficult to identify the favourites.
"You just don't know because the Premier League is so unpredictable these days," he said.
Mourinho won the title in his first season at Chelsea in 2004-05 after inheriting a side that had just finished second.
When he returned to England for a second spell in 2013-14, he finished third with a side that had also come third in the previous campaign but won the title in his second season in charge.