The result sees the Reds now 11 points clear at the top of the Premier League table.
Guardiola said afterwards: "Always with me, the amount of times we arrived in the box the next moment we missed the next action. Our pressing was good. We just missed that in the last moment to do something, that was the performance we know. Against that team, we were really good in many things.
"It was a good set-piece. I don't know if I defend better and sometimes it is not easy if it is a plan. We have the chances and it was the little details that could have gone differently. The wingers were brilliant and in that moment we need to bring the next step. That is what we missed.
"I don't know what would have happened if everyone was here. I don't know if Liverpool would be able to win the Premier League. They are a fantastic team and they are similar in details. They have had no injuries and that is why they could be a stable team and we could not do it. And it is what it is. You cannot achieve what you want all the time. I know how difficult it will be to qualify for the Champions League. I am really pleased with how we have behaved against Newcastle and today.
"I don't want to say if we had Erling Haaland we would have won because that is unfair on the players who played today and gave everything. Of course, with Erling we are a better team. With Rodri we are a better team. With John Stones and Akanji we are a better team and for many reasons with other players we are a better team."