Cristiano Ronaldo is the "greatest football player that has ever lived" but will not turn Manchester United into Premier League champions this season, according to Gary Neville.
Star forward Ronaldo marked his eagerly-awaited Old Trafford return by scoring twice in Saturday's 4-1 win over Newcastle.
Ex-United defender Neville believes his 36-year-old former team-mate ranks above Lionel Messi as the finest individual in the history of the sport due to him being a more complete player.
But, given Ronaldo's advancing years and the strength of rivals Manchester City and Chelsea, Neville expects United to once again fall short in their quest for a first top-flight title since the Sir Alex Ferguson era.
Neville told Sky Sports' Monday Night Football programme: "He does make the team better. I think he makes them more likely to win the title than I thought three weeks ago.
"Something inside me tells me that I don't think he will quite make them the team that will win the title this season. And it's Chelsea and it's City, just in terms of team.
"The introduction of Ronaldo at 36 as a penalty-box striker, which is what he is, I don't think will make them a complete enough team to win the title.
"If Cristiano Ronaldo was seven or eight years younger and was still at that level that he was at Real Madrid, I believe he'd be able to take them to the title or to the Champions League.
"He is a very, very special individual and an unbelievable star.
"I do think he is the greatest football player that has ever lived. That is not bias, that is just me looking at who I would want to trust to win me a football match in the most different ways, who is the most complete player."
Ronaldo returned to United 12 years after leaving for Real Madrid by signing from Juventus at the end of last month.
Neville compared the excitement surrounding the Portugal international's second debut to a Hollywood event.
Asked by fellow pundit Jamie Carragher why the game's purported greatest player would not make United champions, Neville replied: "We're talking about two different things: the greatest player of all time – a player who's had an 18-year career – versus how he now is at 36.
"They are two completely separate things.
"I can say I don't think Manchester United will win the title. However, I caveat that by if that atmosphere and that spirit that I witnessed on Saturday, if that momentum builds, he could do something spectacular.
"I don't think it will happen because I think Chelsea or Manchester City have better teams at the moment than Manchester United."
Neville – an eight-time Premier League champion with United – also believes the top flight of English football has never been stronger and predicts the title race could be a "massive ding-dong".
"I don't think I've seen – in Premier League history – four teams as good as the top four that we've got at this moment and I don't think we've seen the Premier League as good in terms of quality," he said.
"We could have the four best teams in the whole of the world at this moment in time, in Chelsea, United, City and Liverpool.
"We've never had really a true title race of four teams. This could be a massive ding-dong this season. This is absolutely top level that we are witnessing at this moment in time."