Here, is a look at five of the Portugal forward's finest goals during his stint with the Old Trafford club.
Manchester United 2-0 Portsmouth
Premier League: January 30 2008, Old Trafford
Ronaldo had already put United a goal to the good at Old Trafford when he stood over a free-kick some 30 yards from goal. The Portuguese despatched a stunning, swerving, dipping effort beyond a statuesque David James, and later declared the strike the best of his career to that point.
Manchester United 3-0 Tottenham
Premier League: March 20 2004, White Hart Lane
Ronaldo had served notice of his talent with a series of eye-catching displays during his first season in England, characterised by his high-speed stepovers. But he showed there was an end product to his bag of tricks by ending a driving run with a ferocious angled strike for United's third.
Manchester United 1-1 Chelsea (United win 6-5 on penalties)
Champions League final: May 21 2008, Luzhniki Stadium
Ronaldo was already being heavily linked with a big-money move to Madrid when United faced Chelsea in the first all-British Champions League final. The Portuguese further enhanced his reputation with a powerful first-half header from Wes Brown's cross, although he missed a penalty in the shoot-out following a stop-start run-up.
Porto 0-1 Manchester United
Champions League: April 15 2009, Estádio do Dragão
United became the first English team to beat Porto on their own ground as a stunning goal from Ronaldo sent them into the semi-finals of the Champions League. Ronaldo received the ball around 40 yards from goal before running to his right and drilling an unstoppable shot past Helton in the Porto goal.
Manchester United 4-0 Aston Villa
Premier League: March 29 2008, Old Trafford
While not as spectacular as some of the other goals on this list, this opener against Villa perfectly sums up the impudence in Ronaldo's game. A bouncing ball falls to the winger, who quickly readjusted to backheel the ball through a myriad of defenders and into the net.