Mikel Arteta praised his Arsenal team for passing a tough test against West Ham and earning three valuable points in their pursuit of Champions League qualification.
Alexandre Lacazette stepped off the bench to tuck in a winner 12 minutes from time - a goal which was eventually given by VAR after initially being flagged for offside.
However, Arsenal had been pushed hard by relegation-threatened West Ham, with Michail Antonio missing several good opportunities for the visitors at the Emirates Stadium.
"We had the moments of luck we needed but as well it was because we had some really good individual performances at the back, sometimes to clear the ball, sometimes to make the save," said Arteta.
"I'm really happy with the result because big teams find a way, when they don't have the best day - which is obvious, it wasn't our best day in terms of performance - they find a way to win it.
"You can build from there and you can learn and you can take the positives and the negatives in a much better way.
"The unity, the solidarity the players are showing, at the end it pays the price. It didn't pay the price a few days ago when played Olympiakos here but it did today."
Lacazette had begun the match on the bench as Arteta favoured Eddie Nketiah to start - and Arteta says he has a healthy competition emerging between what he describes as his two main central strikers.
"I have two strikers at the moment that make life difficult for me," he said. "At the same time it's very good. They're both scoring, they are both in a good moment.
"I decided to play Eddie today for the type of defenders they had and the game plan we had but knowing that Laca, if we needed a goal in the final moments, he was ready to do that.
"I saw straight away he was alert, he was focused and I could see in his face, that he was really determined to come out there and score the goal like he did."