1. Man City leave it late again

Until this week, Manchester City had not been behind in the Premier League since August but twice they have had to save themselves. Against Southampton on Wednesday, a 96th-minute goal from Raheem Sterling was required for victory. David Silva's winning goal came rather earlier here, in the 83rd minute, but the league leaders are not finding the gears with which they previously blew opponents away. Determination, rather than irresistible flair, is how they managed to maintain an eight-point lead ahead of next week's summit meeting with Manchester United.

West Ham's approach was predictably defensive and manager David Moyes had attempted to copy Southampton's 3-5-2 formation. That set-up had frustrated City (and Guardiola in particular) as West Ham came almost as close to pulling off one of the shocks of the season.

Early on, there were usually nine Hammers camped in the 18-yard box, with only Michail Antonio as a forward player. He served as a distant satellite of Manuel Lanzini, figuratively playing off him but actually sat in the territory of a defence-screening anchorman. That said, West Ham had the first proper chance when Cheikhou Kouyate flicked on a corner but Antonio could not get his foot round the ball.

Meanwhile, City were scratchy. Adrian, playing in West Ham's goal because Joe Hart was ineligible to face his parent club, saved a David Silva shot that came off Declan Rice but when Lanzini had a shot saved rather unconvincingly by Ederson, West Ham had now had the two best chances of the first half and then, their goal came on the stroke of halftime. A short corner was whipped in by Aaron Cresswell and Angelo Ogbonna beat Nicolas Otamendi to a header.

Though City had dominated possession with nearly 73 percent of the ball in the first period, they could not say they hadn't been warned.

The introduction of Gabriel Jesus after halftime was Guardiola's attempt to refresh a stale attacking force, with neither Kevin De Bruyne nor Silva at their best and Sergio Aguero quiet. It was the Brazil international who supplied the equaliser for Otamendi, whose close-range finish off Rice's knee made amends for his part in Ogbonna's opener. From that point on, the game became a session of attack vs. defence, with West Ham desperately clearing their lines but never able to enjoy quality time in possession.

With 20 minutes left on the clock, Jesus forced a great save from Adrian, whose man-of-the-match display brought into question whether Hart should expect to come straight back into West Ham's team. At the other end, Ederson made a decent save himself when Diafra Sakho boomed in a shot on the counter but Silva would, though, have the final say. After De Bruyne at last found space to curl in a cross that Hammers defenders could not get to, Silva stuck out a leg to meet the ball and Adrian couldn't stop the low, bouncing volley from beating him.

City fans sang defiantly of United next Sunday, but this week has suggested vulnerabilities.

2. Hammers better but still in deep trouble

"Take an abacus" had been the advice of one Hammers fan. Moyes was returning to the scene of one of his many humiliations as Manchester United manager, a 4-1 defeat in September 2013 that served as a prelude for much bigger pain to come.

Back in his Everton days, Moyes had a healthy record against City, serving as a constant thorn in the side of then-manager Roberto Mancini. Yet that era feels like ancient history for the manager, with West Ham already looking like another career misstep. He arrived back in Manchester having collected a single point from his three games in charge thus far and though this was a far more heartening away performance than the defeats at Watford and Everton that had fans in open rebellion, his team are in 19th place, a position lower that he inherited.

Those supporters who had made the trip from East London (and via a faulty Sunday public transport network) were still determined to enjoy themselves. "0-0 to the Cockney boys," they sang when their team was holding City. The home contingent, meanwhile, were getting frustrated with West Ham slowing the game down by taking time over throw-ins and breaks in play.

That time-wasting intensified after Ogbonna had scored, with Edmilison Fernandes performing one particularly extravagant piece of playacting as full-time neared, but it wasn't enough to prevent the waves of attack that eventually produced Silva's heartbreaking winner.

3. Man City struggle thanks to Guardiola's selections

With Paul Pogba unavailable for next week's battle royale after his dismissal against Arsenal, Guardiola had taken precautions with Sunday's team selection. Both Vincent Kompany and Fernandinho, on four bookings, were dropped to the bench for emergencies only though Leroy Sane stayed in the team, presumably because he was not expected to be making many tackles.

Fernandinho's replacement was Fabian Delph, whose career revival as a left-back was not replicated in central midfield. One first-half passage of play had Guardiola exasperating on the touchline when Delph held the ball for too long and then conceded possession. The halftime of introduction of Jesus saw Delph restored to life as a full-back.

Kompany's absence gave Eliaquim Mangala his first Premier League start for 568 days, and the French international' partnership with Otamendi betrayed its unfamiliarity as City looked unusually shaky at the back. Neither player is capable of bringing the ball forward from defence in the style of Kompany or John Stones, absent with injury until Christmas.