Manchester - Manchester United manager Alex Ferguson is certain that Wayne Rooney will score 20 goals this season - despite his relatively poor start to the campaign.
The England striker, 27, had a spell on the sidelines with a gash on his knee earlier this season but has only managed three goals in all competitions.
In contrast, Robin van Persie has managed 11 goals since joining from Arsenal in a 24 million ($38 million, 30-million-euro) deal in the close season, while Mexico striker Javier Hernandez has already managed six.
Ferguson, who has a doubt over Jonny Evans for the trip to Aston Villa, feels that persuading Mexico to allow Hernandez to miss this year's Olympic Games in London has made a big difference.
Rooney managed his first Champions League goal in the 3-1 win at Portuguese outfit Braga in mid-week but missed a penalty in the 2-1 victory against Arsenal at the weekend.
Ferguson's side, who lost the title to cross-town rivals Manchester City on goal difference last season, have scored 26 goals in their 10 Premier League matches.
But after last season's problems, Ferguson has calmed concerns about Rooney's opening to the season and has been delighted with Van Persie's start to life at Old Trafford.
"Robin's experienced. He had eight years at Arsenal helps and he's come to us at the right time, there's no doubt," he told a news conference.
"He's got us 11 goals so far and Chicharito (Hernandez) is on six and getting back to what he was a couple of years ago and a summer's rest has helped enormously.
"He's looking fresh and aggressive with his running, always a handful, and Wazza (Rooney) will get to 20 goals plus, I'm sure of that. It's a healthy combination we've got up there.
"Last year we lost on goal difference and I don't expect us to lose on goal difference again and Robin may make that difference. Wayne had goals last year and the way Chicharito has started this season I'm certain he'll get to 20 plus.
"Chicho enjoyed a summer's rest and there's no doubt that the combination they are winning games."
Evans is a doubt for the trip to Villa Park after picking up a minor groin problem in Portugal.
Ferguson is wary of using Chris Smalling, who returned from three months out with groin and foot problems, again after the England defender made his return to action in Portugal.
The United manager admits he may have to press Smalling, 22, into action once again at Villa Park, where Portuguese winger Nani will be absent with a hamstring injury.
Ferguson believes that qualification for the knock-out phase of the Champions League after just four games will be a major boost to his team.
United failed to progress from the group phase for just the third time in their history last season and Ferguson admits that having to push hard in all six games had an impact.
"It's a good position to be in and hopefully we can capitalise and utilise our squad," he added.
"It gives me good opportunities to alter and give people that need a rest a rest but we still want to win the games.
"We've got to go to Galatasary and Turkey is always a difficult place to go. I just think that it's a good position to be in as regards to last season we went to the last game and didn't qualify and it definitely has an impact."