The 23-year-old recorded his 30th goal of the season, an almost fanciful tally for a winger, while his side swept to a 10th straight European win at Old Trafford.
Granted, there were none of the dream-like flourishes that did for Roma last season. That was at the quarter-final stage - this was only the first knockout round, but still United, galvanised by the irrepressible Ronaldo, served enough notice that they were slipping into a higher gear. For Sir Alex Ferguson, this was also a vindication, as he scrapped the hoary adage that you should never change a winning team with a line-up that bore no resemblance to that which had cast Fulham aside so clinically in the league.
There was a sense Ferguson had been mischievous in his meddling for this match, using even the most pivotal of European nights to demonstrate the depth of his eclectic squad. As if the fielding of Darren Fletcher was not a curveball enough, Carlos Tevez found the reward for his strike at Stade Gerland was to be wrapped up against the cold on the Old Trafford bench. In this strange shuffling lay the ruthless genius of Ferguson, from whom his players have come to expect everything and nothing.
Thus Wayne Rooney returned to the role where most believe he is least comfortable, as the genuine lone striker, while Ronaldo was left to wreak merry mayhem on the wing. At first the system looked awkward, each United attack dissolving into speculative drives from distance. Even Ronaldo's first decisive break on the right came to nought as the redoubtable Cris slid in to intercept the Portuguese.
One effective ruse was the deployment of Michael Carrick, who lent some steel to a five-man United midfield and whose penetrating long pass released Nani, only for the 19-year-old to be caught marginally offside. Perhaps Carrick was seeking to reawaken memories of the 7-1 win here against Roma last season, an evening that underlined United's home dominance in this competition and on which he delivered two sublime goals. That was surely his intent when he set himself from 30 yards to force Gregory Coupet into his first save.
The more United suffered, the more Lyon settled. Although the threat of Karim Benzema, perhaps discomfited by his well-publicised spat with strike partner Ben Arfa before this game, never materialised, the French champions have attackers in abundance and Kim Kallstrom drew roars from a raucous pocket of travelling fans when his fearsome drive had to be parried by Van der Sar.
Ultimately, though, United's gift of finding the perfect windows in these games to strike the decisive blow could not be contained. The tense moments just before half-time offered a chance to deflate Lyon psychologically and United, at last adapting to their uncharacteristic 4-5-1 formation, responded. It was not the prettiest of breakthroughs: Anderson, who had increasingly had the ball on a string, fired in a shot that bounced off Rooney, allowing Ronaldo to move wide and beat Coupet from an acute angle. The winger was mobbed by his team-mates at the corner flag while Ferguson, inscrutable to this juncture, pumped his fists with palpable relief.
But the precariousness of United's position was always in evidence. As Rooney continued to be constrained by Lyon's muscular back line, Ferguson finally had to submit to the swelling chant of "Argentina, Argentina". The impressive Anderson duly made way for Tevez, but this heralded the evening's most nervous moment. Kader Keita, himself only just brought on as a substitute, showed a lethal turn of pace in the 74th minute, arrowing a shot beneath the hands of Van der Sar but it rebounded off the post.
United swiftly hit back, Rooney seizing upon a wayward back-pass from Ben Arfa only for Coupet to gather his chip. Tevez was in prime position to add gloss to this victory after a Rooney surge three minutes from time, the but cross was errant.