In a blow to Bernard Tomic’s French Open preparations a virus has forced the Australian No.1 to retire during his first round ATP match in Nice.

Tomic pulled the pin after going down 6-2 in the first set to world No.269 Gianni Mina on Tuesday.

The news was better for two of his compatriots.

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Sixth seed Nick Kyrgios enjoyed a 7-6 (7-5) 6-2 first round win over Russian Mikhail Kukushkin while James Duckworth battled to a 6-7 (7-5) 7-5 6-2 victory over American Frances Tiafoe.

After a stellar start to the year in which Tomic slashed his ranking from No.71 in early January to his current No.28, the Queenslander has dropped off during Europe’s claycourt swing.

He’s had just one win in five claycourt tournaments over the past five weeks.

With his flat groundstrokes, Tomic has typically found slower surfaces not to his liking.

If he is fit for the French Open, which begins on Sunday, he will however enjoy a seeding, protecting him from coming up against another seed in the first two rounds.

Kyrgios used his strong serve against Kukushkin to reach the second round.

The 20-year-old, who is among the outsiders at the French Open after making the final at the Estoril Open and beating Roger Federer in Madrid, lost only two points on his serve in the second set and converted three of his five break chances.

The 30th-ranked Australian will next face Dominic Thiem.

In other games on Tuesday, second-seeded John Isner hit 16 aces to reach the quarter-finals of the Open de Nice in a tight all-American contest with Steve Johnson.

Isner was made to play for nearly two hours by the 55th-ranked Johnson before sealing a 7-6 (7-3) 4-6 6-3 victory.

No.8 seed Juan Monaco also made it to the quarter-finals after he broke Sam Querrey five times in a 6-3 6-1 win.

Seventh-seeded Jack Sock lost 5-7 7-5 6-1 to Dusan Lajovic in the first round and wild card Lucas Pouille breezed past Tim Smyczek 6-3 6-0.