Japanese fifth seed Kei Nishikori reached the round of 16 at the BNP Paribas Open in California with a 7-6(6) 7-6(5) win over American Steve Johnson on Tuesday.

Nishikori, uncomfortable in the blustery conditions at Indian Wells, saved four set points in the first tiebreak and, after failing to serve out the match at 5-3 in the second set, escaped another tiebreak to close out a nearly two-hour battle.

“It’s not easy with these windy conditions and the ball and altitude, everything,” said Nishikori. “It’s tough to expect great tennis here, but I thought I was patient today.”

Nishikori, chasing his second ATP World Tour title of the season after victory last month in Memphis, will next face big-serving American ninth seed John Isner, who fired 15 aces in his 6-4 7-6(4) win over France’s Adrian Mannarino.

Also advancing was German 18-year-old Alexandr Zverev, who crushed 31-year-old Gilles Simon of France 6-2 6-2.

The power-hitting Zverev needed just 67 minutes to advance over 16th-seeded Simon. The German won 70 per cent of his service points and converted five of 11 break points.

“I thought I played really well today,” said Zverev. “I was really ready for a long, long fight and a long three-set match … I’m really happy that I got through so quickly.”

Zverev is bidding to become the youngest quarter-finalist here since 1989 and to reach his first ATP World Tour Masters 1000 quarter in just his fifth tournament at this level.

The teenager may have Rafa Nadal standing in the way as the Spanish fourth seed faces compatriot and doubles partner Fernando Verdasco later on Tuesday.

Defending champion and world No.1 Novak Djokovic will also be in action later on Tuesday as he faces 27th seed Philipp Kohlschreiber of Germany.