Former world number one Murray, who got the better of the German in their two previous meetings, jumped out to a 3-0 lead and seemed to unnerve the 24-year-old by standing well inside the court when returning his second serves.

But Zverev, seeded third, regrouped to win six of the next seven games and took the first set when Murray’s drop shot failed to get over the net.

Just as in the first set, Murray got an early break in the second but Zverev again battled back despite needing a lengthy break to lace up a pair of shoes after the shoelace on his first pair snapped.

Zverev had the match on his racket serving at 6-5 but missed an overhead, a shot that bedevilled him all day, sending the set to a tiebreak.

Murray’s uneven play continued in the tiebreak and after a furious rally of volleys at the net he sent the final one wide on match point, the Scot slamming his racket into the court in frustration.

Zverev told reporters after the match that he felt great.

“I’m happy about how everything went,” he added. “I thought it was a very entertaining match. It was pretty high level, so I’m happy to be through.”

Zverev has now recorded wins against three-time Grand Slam champion Murray, Roger Federer, Novak Djokovic and Rafa Nadal, who were known as the ‘Big Four’ of men’s tennis until injury problems took their toll on Murray.

“This is physically the best I’ve felt in a while, but I’m sort of battling my game a little bit,” Murray said.

“The consistency isn’t there and the decision making is not great in the important moments.”

Zverev will next face either France’s Gael Monfils or South African Kevin Anderson in the next round.

(Reporting by Rory Carroll in Los Angeles; Editing by Peter Rutherford )