No. 1 seed Novak Djokovic posted a 6-4, 6-3 win over Jan-Lennard Struff of Germany in the Olympics men's singles Monday, staying on course to be the first male tennis player to finish off a "Golden Slam," comprising the grand slam plus the Olympic singles gold medal.

Djokovic, who has won 20 Grand Slam titles, was 3-for-3 in break-point opportunities. The Serbian powered 14 aces in the two sets.

"I'm obviously very pumped and inspired to make history," Djokovic told reporters.

Second-seeded Daniil Medvedev, playing for the Russian Olympic Committee team, and German Alexander Zverev, the No. 4 seed, also won on Monday.

Medvedev topped India's Sumit Nagal 6-2, 6-1; Zverev stopped Colombia's Daniel Elahi Galan 6-2, 6-2; sixth-seeded Spaniard Pablo Carreno Busta defeated Croatia's Marin Cilic 5-7, 6-4, 6-4; and Georgian Nikoloz Basilashvili upset the No. 13 seed, Italy's Lorenzo Sonego, 6-4, 3-6, 6-4.

Generali Open

Slovakia's Jozef Kovalik upset ninth-seeded Jaume Munar of Spain 6-4, 6-4 at Kitzbuhel, Austria. Kovalik will take on the Czech Republic's Jiri Vesely, who took down qualifier Ernests Gulbis 6-4, 6-1.

Others into the Round of 16 included Switzerland's Mikael Ymer, a 6-3, 7-5 winner over Uruguay's Pablo Cuevas; Spain's Carlos Taberner, a 3-6, 6-3, 6-2 winner over Brazilian Thiago Seyboth Wild; and Spain's Pedro Martinez, a 3-6, 7-6 (4), 6-4 winner over France's Lucas Pouille.

Martinez will face second-seeded Roberto Batista Agut of Spain.

Truist Atlanta Open

Australia's Jordan Thompson upset eighth-seeded Lloyd Harris of South Africa in a two-hour, 31-minute match, 7-6 (2), 1-6, 6-2 to reach the round of 16 in Atlanta.

Steve Johnson stopped Australian Alexei Popyrin 7-6 (4), 6-3, and American qualifier Bjorn Fratangelo slipped past Italian Andreas Seppi 7-5, 7-6 (5).

The last match of the night saw German qualifier Peter Gojowczyk overtake American Sam Querrey 4-6, 7-6 (3), 7-6 (5). Gojowczyk prevailed despite never getting a break point against Querrey, who had 36 aces. Gojowczyk saved one of the two break points he faced, both in the third game of the match.