The 2-1 loss means City will have to do things the hard way in the Champions League again.
They’ve only won three of their last 12 home games in the competition so West Ham – winners at the Emirates and Anfield already this season – will feel that they have a chance of claiming something when the sides meet at the Etihad on Saturday.
City might be the only side in England still to boast a 100% record, but they were seconds away from giving that up at Selhurst Park last weekend, before Nigerian teenager Kelechi Iheanacho’s last gasp winner.
Whatever happens against the Hammers, Pellegrini’s men will remain top having opened up a four-point gap after five games.
But, despite their early-season superiority, I don’t think they are streets ahead of their rivals.
Even their most impressive result – beating Chelsea 3-0 – had more to do with their opponents’ failings.
West Ham’s last league win at City came at Maine Road in April 2003 and their only victory at the Etihad was recorded in a March 2006 FA Cup tie, but they did beat City 2-1 at the Boleyn Ground last season and can give them a run for their money.
There are question marks over the fitness of key men Sergio Aguero and Vincent Kompany, and Pellegrini needs a plan to handle the attacking threat demonstrated by Dimitri Payet and Victor Moses against Newcastle on Monday.
Slaven Bilic may look to tighten up his midfield by bringing Pedro Obiang into his starting line-up, but West Ham have the players to ask significant questions of a City backline that has yet to concede in the Premier League.
Bilic’s men are joint-top scorers with City and Leicester, having netted in every league game so far.
I’m not convinced it will be as easy for the hosts as odds of 1/4 suggest.
The Hammers are 10/1 with Sportingbet and backing them at 14/5 with the same firm with a +1 handicap appeals. Spread bettors should sell City’s supremacy with Sporting Index at 1.85.
West Ham +1 14/5 (Sportingbet)
Sell City supremacy 1.85 (Sporting Index)