Sir Alex Ferguson said he abandoned plans for wholesale changes against Everton once Manchester United were offered "a fantastic position" in the title race by Manchester City's defeat at Southampton. United obliged with a 2-0 defeat of David Moyes's team to establish a 12-point lead in the Premier League, their biggest advantage for 12 years. Yet Ferguson refused to accept the title race is over.

"No, no, no" was the United manager's response to the suggestion that a 20th league title is on its way at Old Trafford. "The plan is to win our next game, then the next game and then the next one. That is the only thing you can do. Eventually, the games whittle away."

Ferguson claimed on Friday that he would field two different teams against Everton and Real Madrid, whom United face in the first leg of the last-16 Champions League tie at the Bernabeu on Wednesday. City's 3-1 defeat at St Mary's Stadium, however, prompted a change of mind. Only Rio Ferdinand, Michael Carrick, Ashley Young and Shinji Kagawa were rested from the starting line-up against Everton and first half goals from Ryan Giggs and Robin Van Persie sealed victory.

"I was going to make seven changes," Ferguson said. "Then when I got the [City] result I thought this would be a more important game for us. It would give us a comfortable lead and we could make changes later on in the season. Realistically we knew if we got a result it would put us in a fantastic position. We have to win our games anyway. It doesn't matter what happened to City. That is the way we should look at it. I've said it for weeks – concentrate on our own game and we'll be OK."

Giggs's goal maintained a remarkable record – he has scored for United in each of the past 23 seasons. The 39-year-old made his debut against Everton in March 1991.

Ferguson said: "I think all the superlatives have been used and he doesn't need any more because his legacy lives on. He's just a fantastic human being. In this game again, at 38 years of age, or is he 39?

"Maybe 40, I don't know, but he's up and down that pitch all day and showing fantastic energy for the game. It's wonderful to see."

José Mourinho was at Old Trafford and said the Champions League tie would be one to savour. "It is the match the world is waiting for," the Real Madrid coach said. "The world is not waiting for other matches in the Champions League so I hope we can give the world what they are waiting for."

Phil Jones and Jonny Evans will be assessed at Carrington on Monday after suffering injury against Everton. "Jones took a knock on his calf while Evans had a bit of cramp," Ferguson said.