The forward was not able to net in their 0-0 Champions League group stage draw with Inter Milan.
However, Haaland has been prolific so far this term, netting nine goals in four Premier League games.
"There were six players around him," Guardiola said while gesturing wildly in his press conference.
"Six. Three behind, three in front. That's how they kept him out of the game.
"That makes it difficult for any player. (Francesco) Acerbi, (Alessandro) Bastoni were five metres away from him, (Hakan) Calhanoglou, (Piotr) Zielinski in front of him. That's tough.
"We tried to use the spaces, that's why (Ilkay) Gundogan had a couple of chances but Inter were stronger than us physically. We needed to get more players up alongside Erling and that's what we did. I knew that Inter would defend like that."