Earlier, former Wimbledon finalist Matteo Berrettini battled back from a set down to knock out German top seed Alexander Zverev.

Defeat for second-ranked Zverev means that Jannik Sinner is guaranteed to remain as world number one when he returns from his three-month doping ban at the Italian Open in May.

Zverev twice broke Berrettini's serve in a commanding opening set but the Italian seized his first opportunity of the match in set two to force a decider.

Berrettini served for the match at 5-3 in the third, but Zverev responded with a good return game to level the set.

However, Berrettini broke once again and held his nerve to serve out a tense 68-minute third set.

Following the biggest win of his career by ranking, Berrettini awaits either compatriot Lorenzo Musetti or Czech Jiri Lehecka in round three.

Also on Tuesday, defending champion Stefanos Tsitsipas came back from a set down to beat Australian Jordan Thompson 4-6 6-4 6-2.