Alex Ferguson has warned Manchester United's title rivals that revitalised Mexico striker Javier Hernandez will play a significant role in the battle for the Premier League. While Robin van Persie and Wayne Rooney hog most of the headlines and attention from opposition defenders, Hernandez has quietly gone about his business in clinical fashion this season. The 24-year-old Mexican took his tally to 10 goals for the campaign with his last-minute winner in United's 4-3 win over Newcastle on Wednesday and Ferguson believes he has rediscovered the dynamic form that made him such a hit in his debut season after a disappointing effort last term. With Rooney sidelined with a knee injury, Hernandez ensures defences can't just focus on shutting down van Persie and his strike against Newcastle allowed United to open up a seven-point lead over second placed Manchester City. Ferguson, whose side will look to extend that advantage when they host West Bromwich Albion later Saturday, said: "He has been doing it all season. "Every time Javier has played he has contributed. He has got 10 goals now and that is despite not playing every week. On Wednesday he could have scored four or five. "Javier's effort and enthusiasm to play is absolutely fantastic. He is a great example to anybody who wants to be a footballer. "He is exactly the same in training and gives 100 percent in every session." Meanwhile, City's title defence was dealt a potentially decisive blow in a 1-0 loss at Sunderland on Wednesday, and Saturday's opponents, Norwich, have been beaten at home just twice all season. The champions' odds of retaining their crown are lengthening by the week, but manager Roberto Mancini says he is not fazed by his side's seven-point deficit. "It hasn't changed. At this moment, United are better than us, they are at the top, but we have time to recover," Mancini said. "We need to resolve our problems before and after, maybe we can win. It's no problem, seven points. "That's not important. We know United are a fantastic team and probably they will win every game, but the season is long and it is not important if it is six or seven or four points." City's setback enabled Chelsea to close to within four points of second place by winning 1-0 at Norwich and Rafael Benitez's side -- 8-0 victors over Aston Villa in their previous game -- also have a game in hand. On Sunday, last season's Champions League winners visit fifth-place Everton -- one of three teams in the table on 33 points, along with Tottenham Hotspur and West Brom. Arsenal lost ground in the battle for a top-four finish, and Champions League qualification, after their Wednesday game with West Ham United was cancelled due to a strike on the London Underground transport network. The Gunners have therefore benefited from an unexpected period of rest at a time when their rivals' resources have been stretched, but midfielder Jack Wilshere says his team-mates will have to switch on quickly when they return to action at home to Newcastle on Saturday. "It's a tough game against Newcastle," he said. "They need the points, they're not in a good run of form and they'll want to prove something, but we want to keep this momentum going." Queens Park Rangers, who returned to the foot of the table after losing at home to West Brom, host Liverpool on Sunday, while second-bottom Reading tackle West Ham on Saturday and third-bottom Wigan Athletic are at Villa. Fixtures (1500GMT unless otherwise stated) Saturday: Sunderland v Tottenham Hotspur (1245GMT), Fulham v Swansea City, Reading v West Ham United, Aston Villa v Wigan Athletic, Stoke City v Southampton, Manchester United v West Bromwich Albion, Norwich City v Manchester City, Arsenal v Newcastle United (1730GMT) Sunday: Everton v Chelsea (1330GMT), Queens Park Rangers v Liverpool (1600GMT) Source : AFP