Having his first proper pre-season as a Manchester United player helped Javier "Chicharito" Hernandez get in playing shape, Sir Alex Ferguson said Friday ahead of the team's highest-profile match of the season at Stamford Bridge vs. Chelsea (Sunday, 12 p.m. ET)
"The thing that is making the difference is he got a proper rest in the summer," said Ferguson. "It wasn't exhausting in the way it had been in the previous three years. He was tremendous the other night. He is such a dedicated footballer and professional in every training session."
United has four tough games in 10 days. It plays at Chelsea twice, including a League Cup match, and then hosts Arsenal before travelling to Portugal for Braga.
Chelsea, with Frank Lampard out due to a recurring right calf injury, is coming off impressive away wins at Arsenal and Tottenham.
Chelsea, the European champions, have won seven of their eight league matches to power into a four-point lead. Yet, while Chelsea is unbeaten in the league, the team fell to the first loss in its defense of the Champions League title with a 2-1 defeat at Shakhtar Donetsk on Tuesday.
Ferguson caused controversy when he put a block on Hernandez being selected for Olympic duty this summer. Mexico went on to claim the gold medal by beating Brazil at Wembley.
Hernandez, 24, saw benefit Tuesday, when he scored twice to rescue United in their Champions League encounter with Braga at Old Trafford.
Previously, Hernandez did duty at both the World Cup and Gold Cup, the regional tournament for the CONCACAF region at which he ended up top scorer.
And with the Confederations Cup, and another Gold Cup due to take place in 2013, and the World Cup to follow that in Brazil 12 months later, Ferguson said missing London 2012 was essential.
"He's a really terrific player and the good thing is that he is still improving," Ferguson said.
Hernandez's double means he has now scored three times this season, a tally bettered only by Robin van Persie in the United squad.
Given Chelsea's new-found creativity up front, led at the moment by the imperious Juan Mata, United's shaky defense is sure to come under serious pressure at Stamford Bridge.
With Sunday's match in mind, Rio Ferdinand and Patrice Evra were rested for the 3-2 win over Braga in the Champions League on Tuesday but center back and captain Nemanja Vidic is still out with a knee injury.
"We have had some great battles with them down the years, but they have changed quite a lot very quickly," United defender Jonny Evans said of Chelsea. "You can see that from the way they have been scoring their goals this season.
"They scored four again at the weekend so it's going to be a tough game and our record down there has not been great over the last few seasons, so that makes it a bit harder still."
John Terry will be absent as he serves the second match of his four-game domestic ban for racially abusing QPR defender Anton Ferdinand in a league game last October.
The repercussions of that on-field incident have been vast, including a worsening in relations between Rio Ferdinand, Anton's older brother, and Chelsea defender Ashley Cole, who gave evidence on behalf of Terry in a criminal court.
In the latest handshake saga in the Premier League, Ferdinand is widely expected to snub Cole in the pre-match protocol. United is set to be without Shinji Kagawa, who has a knee injury.
For United, Van Persie and Wayne Rooney are in line for a starting role, while Danny Welbeck has started five Premier League games so far compared to Hernandez's single effort, against Wigan last month.
"It's a good problem to have," said Ferguson of the choice he will have to make regarding starters. "I don't always enjoy it [telling players they're not playing] but it has to be done. In fairness to all the players they've accepted it well and adapted to it.
"I don't have any great problems other than having to tell one or two of them they're not playing."
Information from The Associated Press and Press Association was used in this report.