Wayne Rooney scored his second successive hat-trick as rampant Manchester United stormed back to the top of the Premier League with a 5-0 win at Bolton Wanderers just hours after Sergio Aguero's treble briefly lifted Manchester City into first place on Saturday.Rooney scored three times in United's 8-2 demolition of Arsenal before the international break and the English forward picked up where he left off to claim the seventh hat-trick of his career.He converted two crosses from Phil Jones in the first half and then swept home a Ryan Giggs pass after the break to take his goal tally for the season up to ten for club and country.United's blistering display, which also included two goals from Mexican forward Javier Hernandez, means the champions have now scored 18 goals in their first four matches, a new Premier League record for this stage of the season that keeps them ahead of title rivals City on goal difference."We got an early goal and kicked on from there and it could have been more," Rooney said. "I had a long time to rest and get a good pre-season under my belt. I've stayed free of injuries and it's helped me for the start of the season."The only downbeat note for United manager Sir Alex Ferguson was an injury to Tom Cleverley, which forced the young midfielder to come off in the first half. "We kept playing our football. That is what we are here to do. We withstood all the challenges and just got on with it," Ferguson said. Earlier, Argentinian international Aguero starred as Roberto Mancini's City outclassed Wigan Atheltic 3-0 at Eastlands with a mesmerising display of attacking football.The victory maintained City's perfect start to the season and manager Mancini was purring with pleasure after the virtuoso display of Aguero, signed for a club-record £38 million from Atletico Madrid this summer. From / FIFA