Cristiano Ronaldo of Manchester United shoots and scores their first goal in the match against Tottenham Hotspur on March 12, 2022 in Manchester, England. Photo: VCG

Ralf Rangnick admitted managing Cristiano Ronaldo is "challenging" after the 37-year-old rolled back the years with a hat trick to beat Tottenham 3-2 and keep Manchester United's chances of playing in the Champions League next season alive.

The five-time Ballon d'Or winner had scored just once in his previous 10 games, but three fantastic finishes took him clear as the highest scorer in professional men's football history according to FIFA's records with 807 goals for club and country.

Ronaldo's second spell at Old Trafford has so far proven to be an anti-climax with his poor form sparking debate over whether his powers are waning. 

He missed United's thrashing in the Manchester derby last weekend and was criticized for a perceived lack of commitment as he jetted off to Portugal to rehab a hip injury rather than watch his teammates lose 4-1 at the Etihad after reports he would have been dropped by Rangnick even if fit.

"It is challenging with players like him but he showed today he still has the quality to play for Manchester United," said Rangnick. "He's part of the team and if we want to be successful we have to do it together."

"Today it was his best performance, at least since I arrived. Not only because he scored three goals, but he was also energetically good today and part of the whole team when we had to defend. A top performance by him, but also the rest of the team."

Victory lifts United back into fourth, although they are just two points ahead of Arsenal who have four games in hand.

A fifth defeat in eight league games is another blow to Tottenham's hopes of a top-four finish as they remain seventh, now five points behind United.

In front of seven-time Super Bowl champion Tom Brady, Ronaldo was keen to show his own greatness as he was restored to Rangnick's starting lineup as one of five changes with Bruno Fernandes the notable absentee due to illness.

It took just 12 minutes for him to make his mark with a stunning strike into the top corner from outside the box.

However, United failed to build on the early goal and were instead forced back in a familiar pattern to previous home games this season against stronger opposition.

A Tottenham equalizer seemed only a matter of time and was gifted to them when Alex Telles handled Dejan Kulusevski's cross for a clear penalty. Harry Kane smashed home the resulting spot kick.

Within three minutes, though, United were back in front thanks to a landmark goal for Ronaldo.

He turned home Jadon Sancho's inviting cross to surpass Austria-Czech striker Josef Bican as football's all-time record goalscorer according to FIFA's records.