Alex Ferguson knows all about the value of a good substitute and if Manchester United win another Treble this season, he might just add Nani to his list of crucial game-changers.
Deemed to be surplus to requirements when Ferguson named his 18-man squad against Real Madrid last week, Nani may not even be at Old Trafford next season following Wilfried Zaha's January capture from Crystal Palace.
But after replacing the injured Phil Jones three minutes before half-time, the Portuguese winger scored one and made the other as United overcame a resilient Reading to secure an FA Cup quarter-final at home to either Middlesbrough or Chelsea.
Back in 1999, when United last won the Treble, it was due to the likes of Ole Gunnar Solskjaer and Teddy Sheringham winning games from the bench.
Nani's contribution might not match Wembley or the Nou Camp in terms of significance, but United's were stuttering until he made the difference here.
Maybe it was the opposition, perhaps it was the Monday night kick-off, but after the drama and excitement of Real last Wednesday, Old Trafford struggled to rouse itself for the visit of Brian McDermott's team.
Having made eight changes to his starting line-up from the 1-1 draw in the Bernabeu five days earlier, Ferguson also hinted at a sense of United subconsciously regarding this game as just another routine fixture to tick off on the road to a possible Treble.
Reading's run of five victories from seven games pointed to their confidence, however, and their ability to get under United's skin was highlighted by their success in emerging with draws from their last two visits to Old Trafford.
With Wayne Rooney missing as a result of sinus infection which, according to Ferguson, had left the forward bedridden since Sunday morning, United began with Danny Welbeck and Javier Hernandez as their strike pairing, with Ashley Young making his first appearance since suffering a knee injury against Liverpool five weeks ago.
All three of those players should have opened the scoring in the early stages as United attempted to ignite the slumbering crowd.
With just two minutes on the clock, Reading defender Adrian Mariappa had produced crucial blocks to deny Hernandez and Welbeck before Antonio Valencia's header was saved by Adam Federici. Welbeck was then denied by the Australian goalkeeper when his shot from Young's pass was pushed behind for a corner.
Federici, whose performances have been hit and miss since promotion to the Premier League last season, was enjoying one of his better nights and he pulled off a double save from Tom Cleverley and Young on 22 minutes as United increased the pressure.
Reading, whose only win against United came way back in 1927, struggled to threaten, partly due to striker Noel Hunt spending more time off the pitch than on it in order to receive treatment for a gashed head following a challenge by Nemanja Vidic.
A further injury to United defender Jones, who limped off with an ankle problem sustained in a challenge with Jobi McAnuff, added to the disjointed nature of the first-half.
Nani almost broke the deadlock two minutes after entering the fray with a right-foot strike which rattled the foot of the post.
Seconds earlier, United goalkeeper David de Gea had kept out Adam Le Fondre's 30-yard effort with a full-stretch save.
When these two teams last met, at the Madejski Stadium in December, a flurry of goals saw United lead 4-3 after just 34 minutes, yet while there were enough chances for a similar flow of goals on this occasion, both goalkeepers were exceeding themselves in terms of keeping the ball out of the net.
And when defender Shaun Morrison blocked Cleverley's 50th-minute strike, it appeared as though United were destined to record their first 0-0 draw in 101 games – their last being a stalemate at Newcastle in April 2011.
The torpor within Old Trafford had become so evident that Ferguson felt the need to instruct one of the ballboys to race around the perimeter of the pitch to tell the army of hoodie-wearing youngsters to speed up their delivery of the ball when it had gone out of play.
Anderson then waved his arms at the crowd in an effort to raise the volume after he had seen a shot saved by Federici on the hour.
Nani made the breakthrough on 69 minutes, though, when he took a touch to control Valencia's pass before sending a left-foot strike past Federici from 12 yards.
With their resistance broken, Reading then conceded another two minutes later when Nani's pinpoint cross from the right was headed in at the near post by Hernandez.
McAnuff gave Reading a glimmer of hope when he scored from close range, but United were in the ascendancy and the goal proved no more than an irritating statistic. (© Daily Telegraph, London)