The Hammers remain fourth - the highest-placed club in London - in the Premier League despite their valiant defeat by Pep Guardiola’s side, who sealed a 20th consecutive victory across all competitions at the Etihad Stadium.
West Ham came desperately close to taking what would have been a deserved point when Issa Diop headed wide in injury time, but the result did nothing to dampen hopes of a push for Europe this season.
"We feel a bit sad because we did a lot of things to take a point," said Fornals. "But I think all our supporters have to be proud of this team, how we played against the best team in the Premier League right now. Of course we are upset but happy for how we played.
"When you see their starting XI you just think what a good team they have, you look at the bench as well and the people there are probably better than those playing. It is not easy to come here, in their stadium, and compete with it."
David Moyes's side restricted City's forward line well - it took goals from two central defenders for the hosts to win - and showed ambition going forward, as they are now doing on a consistent basis in another sign of how the Hammers are progressing under the Scot.
“I thought you saw a different West Ham, one which was confident and really believed they could take it to City," said captain Declan Rice.
“A year ago, we’d have a couple of games when we were good, then have games when we were poor, but now you can see our performances week in, week out - we’re leaving everything on the pitch."