By ROB HARRIS AP Sports Writer LONDON (AP) -- With Manchester United closing in on a 20th English championship title, Manchester City is discovering that not even investing more than $1 billion on players can guarantee success over a unified and settled squad. Man City had been predicted by many to win a first English league title since 1968 after its massive outlay on players. But the Abu Dhabi-owned club has lost a five-point lead to allow defending champion United to surge eight points clear with six rounds left. United's advantage could grow further after today, when it plays Wigan and City meets West Bromwich Albion. A successful title defense for United could even be clinched at City's Etihad Stadium on April 30, completing a remarkable turnaround for the team after being beaten 6-1 in the October derby. "It would be huge (winning the title) when you look at the spending power Manchester City have, the injuries we've had, the experience we've lost -- Scholesy (Paul Scholes) for half the season, Edwin van der Sar, John O'Shea, Wes Brown," United midfielder Ryan Giggs said. "Then the challenge we faced bringing in a new goalkeeper -- David de Gea came in for a lot of criticism early on but he's worked hard and he's showing terrific form at a key time -- and the young talent we've blooded in, it would be a massive achievement." Giggs has been part of United's 12 title-winning sides in the previous 19 seasons, while City has only starting becoming a credible challenger since the first injection of funds from Abu Dhabi's royal family in 2008. City also needs to learn about team unity, with the squad imploding of late after having made an electrifying start to the season. Carlos Tevez's feud with the club after refusing to warm up during a Champions League match in September kept him out of the team for six months. Manager Roberto Mancini has also had to deal with another troublesome striker, Mario Balotelli, whose conduct on and off the pitch has been a constant distraction. Mancini said the gifted-but-flawed Italian is likely to be sold in the offseason after he was sent off in Sunday's loss at Arsenal. The red card came after a second lunge on Bacary Sagna and, when considered with previous indiscretions, could lead to Balotelli being banned for nine matches by the English Football Association. But the aggravation caused by Balotelli and Tevez is not the only reason for City's collapse. After beating City 1-0 on Sunday, Arsenal can strengthen its grip on third place with a victory at bottom-place Wolverhampton Wanderers on Wednesday. The Gunners have a two-point advantage and a game in hand over Tottenham and Newcastle.