Arsenal boss Mikel Arteta praised his side's mental strength after Eddie Nketiah's late winner maintained their 100% start to the season against West Ham.
The result condemned the Hammers to a second successive defeat - the third time in the past four seasons they have lost their first two matches.
"What I like is the approach the boys had in the last 25 minutes where I could see they were a bit down and then they lift it," Arteta said.
"Probably a few months ago we would have drawn or lost that game and today we win it.