City won 3-1 thanks to goals from Omar Marmoush, Bernardo Silva and Nico Gonzalez, leaving the team in third place on the Premier League table.
However they still need a point from their last game of the season at Fulham to be sure of Champions League qualification.
“We need to get a result there,” said Guardiola.
“We have a final in London and it will be so tough to take the point that we need but it’s really important.
“To be in the Champions League after what has happened this season would be nice.”
Kevin will be missed
Last night's win marked the final home game as a City player for Kevin de Bruyne.
Guardiola also said: “The important thing is the emotion for him, his family and our fans.
“The vibe we got and everybody saw how much everyone is connected. City and his family. How much love there is.
“Titles are nice to achieve but when you live in a place after a decade with this much love, respect and gratitude there is nothing better than that.
“It is a sad day and he will be missed, there is no doubt about that. He made the contribution to achieve the victory that is massively important.
“Still we need the last step. It’s been really, really nice.”