The seventh seed has marched into the last 32 without dropping a set following his 7-6 (7-5) 6-4 7-5 victory over Egor Gerasimov on Thursday.

Yet to reach the quarter-finals of a hardcourt or grasscourt major despite climbing as high as No.3 in the world and winning the 2018 season-ending championship, Zverev arrived at the season's first slam low on confidence and down on form.

Suffering from an alarming case of serving yips, he coughed up 34 doubles faults in losing all three of his matches at the ATP Cup to Alex de Minaur, Stefanos Tsitsipas and Denis Shapovalov as Germany bombed out in the pool stages.

But the 22-year-old appears to be finding his groove on Melbourne Park's faster surface, Zverev needing little more than two hours to see off Gerasimov.

Zverev led a batch of big-name challengers to heavyweights Rafael Nadal, Novak Djokovic and Roger Federer into the third round on Thursday.

His only hiccup came when he dropped serve trying to close out the match at 5-3 in the third set, before he regrouped to break the Belarusian for a third time to book a third-round date on Saturday with Fernando Verdasco or Nikoloz Basilashvili.

"Definitely much better than the ATP Cup. Now into the third round, I'm very happy about that," Zverev said, revealing he practised "six, seven hours a day" last week in a bid to iron out the chinks.

"To find my serve, my groundstrokes, whatever hasn't been working at the ATP Cup."

Fourth-seeded Russian Daniil Medvedev overpowered Spanish qualifier Pedro Martinez 7-5 6-1 6-3 to tee up a Wimbledon rematch with 20-year-old Australian prospect Alexei Popyrin.

Medvedev banged down 19 aces, had 40 winners and broke his opponent six times but wasn't entirely happy with the performance.

"Still, the first set I wasn't always happy with my first serve," the 2019 US Open finalist said.

"But we are tennis players, we always want more."

Popyrin kept up his end of the bargain with a 6-2 7-6 (7-5) 7-2 win over Spaniard Jaume Munar to match his run to last year's third round on his Open debut.

Australian wildcard Bolt gave fifth seed Dominic Thiem a fright, forcing the dual French Open finalist to battle from two sets to one down before progressing 6-2 5-7 6-7 (5-7) 6-1 6-2.

Thiem will play either American Taylor Fritz or South African Kevin Anderson next Saturday.

Australian Associated Press