Following his three-and-a-half hour match win over the Serbian, Zverev became enamoured with the distinct British accent when radio broadcaster Jonathan Pinfield asked whether Roland-Garros could be a turning point in his career.
Despite calling on a trainer to treat blisters on his left toes before the start of the fifth set, the world number three zipped around easily to break in the opening game of the decider and finished off the 38th-ranked Russian after three-and-a-half hours of pulsating action.
German Zverev, 21, beat the unseeded Russian 4-6 7-6 (7-4) 2-6 6-3 6-3 in three hours 29 minutes in an enthralling match in Paris. Keys held steady, though, and was able to convert her second match point when Osaka double-faulted.
He will next play either seventh seed Dominic Thiem, who completed a 6-2 6-0 5-7 6-4 win over 19th seed Kei Nishikori. It's not about, I'm going to try to do this, try to do that in the third set, I'm going to do this in the fourth set or something like that. In the victory, Zverev won 60 percent of his first serve points and 52 percent of his second serve points.
"It was an unbelievable, high level match", added Zverev. Zverev wasn't at his best, as he was broken eight times and racked up 59 unforced errors.
"It was the first time I have won on this court and I hope there are many more to come".
A tense fourth set unfolded, with Dzumhur- who at one stage collided with a ball boy - breaking for a 3-2 lead.
Not everyone was winning this week, though - especially one of the ball boys.
"I made a few mistakes which I really shouldn't", said Dzumhur.