It was the standout moment of his second spell at Old Trafford, which has been topsy-turvy.
Here the PA news agency looks at his time with United so far this season.
What has Ronaldo’s impact been since returning to the club?
Having been tipped to make a controversial switch from Juventus to rivals Manchester City, the 37-year-old instead returned in August for an initial £12.86million to the club he left in 2009. Ronaldo made his second debut for the club in front of a packed, expectant Old Trafford on September 11 and did not disappoint, scoring twice in a thumping 4-1 victory against Newcastle. The forward scored in four of his first five United games and enjoyed an impressive first half to the season. His form tailed off at the start of the year, scoring just once in 10 games before returning to his best against Spurs.
What did he walk into?
United have stuttered since Sir Alex Ferguson’s retirement in 2013, with the despised Glazer family’s ownership providing a challenging backdrop. The club appeared to be on the right track on the field last season as Ole Gunnar Solskjaer oversaw progress, finishing second in the Premier League before losing an agonising penalty shootout in the Europa League final. The summer arrivals of Ronaldo, Jadon Sancho and Raphael Varane heightened hope and expectation, but things unravelled this term as chastening losses against Liverpool and City helped send United into a tailspin. The humiliating 4-1 loss at embattled Watford in November led to Solskjaer’s exit and while Ralf Rangnick has steadied the ship, results and performances have been patchy.
Has Ronaldo been an effective signing?
Some have suggested Ronaldo has had a big part to play in United’s struggles, but that would be foolish. Without him the club would almost certainly be out of the Champions League, plus only Mohamed Salah has scored more times in the Premier League than the Portuguese. Rangnick has admitted that he is challenging to manage and he has not always fitted into United’s style of play. But, as with great players, he is often the difference between winning and losing for United, with his hat-trick against Spurs the perfect example of why he still so important to them.
What next for Ronaldo and United?
Ronaldo is a standard-bearer at United. He may not wear the captain’s armband but he is a leader on the pitch with his big-time contributions. Doubts surrounding his future have been raised in the aftermath of a heavy Manchester derby defeat and a decision will surely be made at the end of the season. But at 37 and with a new manager due to arrive in the summer, he is definitely not the long-term solution to ending United’s time away from the elite. But having declared there are “no limits at Man Utd” in the wake of the win over Tottenham, Ronaldo looks set to play a key part in the club’s quest to finish in the Premier League’s top four. There may well be more stories to be written in the Champions League ahead of a last-16 second-leg tie with Atletico Madrid.