The Portugal international's 28th-minute strike handed United a 1-0 victory at Sunderland yesterday and kept them a point behind Premier League leaders Chelsea.
However, with just one game to go, the odds are heavily stacked against them.
Sir Alex Ferguson's men entertain Stoke at Old Trafford next Sunday knowing victory will not be enough if the Blues beat Wigan at Stamford Bridge, but no-one within the Red Devils camp is throwing in the towel.
Nani said: "We are still a team, we are together and we will fight until the last chance.
"We still have a chance. You never know what is going to happen in football. Sometimes in life, it is very difficult, but we have to win our game."
Goalkeeper Edwin van der Sar too knows only a shock result for Wigan will send the trophy to Old Trafford, but is confident United will do their job and then keep their fingers crossed.
He said: "We need a big favour from Wigan. It would have been nice if we had been a point ahead.
"We are not in charge - that is difficult - but we have to see what we can do this week on the training ground.
"Hopefully everyone will have recovered from this match and we have a nice game for our supporters on Sunday.
"We are still hanging in there."
Whatever happens next weekend, United made sure Chelsea had to wait for their chance to clinch the title with a powerful display at the Stadium of Light.
In truth, they might have won far more comfortably, but passed up a series of chances to kill off Steve Bruce's side.
Bruce is yet to beat his former boss Ferguson as a manager and apart from a brief first-half flurry, he never looked like addressing that issue yesterday.
John Mensah and Lorik Cana both went close with first-half headers and Steed Malbranque forced a flying save from Van der Sar, but from the moment Nani drilled the visitors ahead with a perfectly-struck right-foot drive, the points were effectively safe.
Craig Gordon had earlier denied the fit-again Wayne Rooney and made a fine second-half stop from Nani, but it was Bulgaria international Dimitar Berbatov who was the guilty man on a day when the second goal simply would not come.
Berbatov squandered a glorious opportunity at the end of the first half and then twice missed the target from point-blank range after the break on an afternoon to forget on Wearside.
But with Van der Sar a virtual spectator for much of the game, those misses did not prove too costly.
United completed their 37th game of the league campaign having conceded just 28 goals, the best record in the division, and the Dutchman, who kept his 13th clean sheet of the season at the Stadium of Light, is hoping that can provide the foundation for another title challenge next time around.
Van der Sar said: "That is very good. We had it last year also. We didn't concede many goals. We had a great run of clean sheets.
"It has been a bit back and forth this season with midfielders in defence and right-backs at left-back or whatever, and a couple of goalkeeping changes.
"It is a positive point to take into next season. Maybe we can improve the goals scored."