With Manchester United closing in on a 20th English championship title, Manchester City is discovering that not even investing more than $1 billion ($A973.09 million) 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.

That advantage could grow further after United plays Wigan and City meets West Bromwich Albion on Wednesday.

City winger James Milner says “we have brought players in and it takes time for them to settle, coming from abroad or from other clubs, and gelling as a team.”