Guardiola has faced some criticism over his side's failure in Europe's premier club competition despite having twice claimed the title while managing Barcelona.
But Valverde believes Guardiola, who could still lead City to a domestic treble this season, still holds the crown as the best tactician in the world in his eyes.
"For me, the best coach is Pep Guardiola, no doubt about that," he told a news conference on Friday.
"Even if he was kicked out of the Champions League."
Barcelona will face Liverpool in the Champions League semi-finals, while they are also closing in on the La Liga title ahead of hosting Real Sociedad on Saturday, and Valverde was quick to point out the dangers of facing Jurgen Klopp's Reds.
"Last year they were in the final, this year doing well in [Europe] again and they're fighting for the Premier League, too," he said.
"So, it's a really tough tight for us but it's an attractive one for everyone."
But the Barca boss is not looking ahead too far, with his side looking to wrap up La Liga before ever taking on the Premier League side.
"The final's on the horizon and we will do everything to win," he stated. "That said, it's all well and good to talk about Liverpool, but it's a long way away still. We have really important games before then in La Liga."
Barcelona have opened up a nine-point gap on the rest of the Spanish top flight through 32 matches.