The Gunners won their preseason friendly 2-0 at Emirates stadium.
"Sometimes it’s like this, we have to win the games on set-pieces and we did so well today,” he told arsenal.com after the match.
“After last season, we have to be so good on set-pieces and we started well today and have to keep going like this because we can win a lot of games on set-pieces.
“I’m happy because I think we played well. It wasn’t easy because it was so hot today and they were not bad, we played against a good team. We did our job, of course we could have scored more goals. It’s good for us to be prepared for next week against Wolves.”
On debut boy Riccardo Calafiori, Saliba added: “Yeah, I’m so happy for him.
“I think it’s only the beginning, he’s a really good player, young as well. We’re so happy to have him with us and I hope he’ll have a really good season with us.”