MONACO (AP) -- Karen Khachanov was clinical on his serve in a 7-5, 6-4 win against Thanasi Kokkinakis of Australia in the first round of the Monte Carlo Masters on Sunday.
The big-serving Russian had five aces and did not face a single break point. He might even have made the win more comfortable.
Kokkinakis recently beat 20-time Grand Slam champion Roger Federer in the second round of the Miami Open - becoming the lowest-ranked man to beat a No. 1 in 15 years - but the powerful Australian could not produce anything like that form this time.
Khachanov constantly pressured his opponent's serve, yet could only convert two of his 13 break points.
Khachanov, who won his second career ATP Tour title at the Open 13 in Marseille in February, next faces either Gilles Simon or 16th-seeded Adrian Mannarino.
If he beats the winner of that all-French match, Khachanov could face defending champion Rafael Nadal in the third round.
Nadal has a first-round bye and plays Aljaz Bedene or Mirza Basic in round two. The 10-time champion needs to win the tournament or Federer regains top ranking.
In Sunday's other first-round matches, there were wins for Mischa Zverev of Germany and Daniil Medvedev of Russia.
Zverev labored to a 6-2, 6-7 (4), 6-1 win against 17-year-old Canadian Felix Auger-Aliassime, and next faces seventh-seeded Frenchman Lucas Pouille.
Medvedev rallied to beat Marton Fucsovics of Hungary 6-7 (4), 6-2, 7-5, saving seven of eight break points. He meets either Kei Nishikori of Japan or 12th-seeded Czech Tomas Berdych, the 2015 runner-up. They play Monday.
Two-time champion Novak Djokovic, still struggling with a persistent right elbow injury, is also in first-round action Monday.
The ninth-seeded Serb, who recently split with coach Andre Agassi, takes on countryman Dusan Lajovic. He beat Lajovic in their only previous meeting three years ago.
Jerome Pugmire on Twitter: www.twitter.com/jeromepugmire