Third-seeded Karen Khachanov, playing in his hometown of Moscow, rallied for a 3-6, 6-3, 6-1 win over Australia's James Duckworth on Wednesday in the second round of the VTB Kremlin Cup.
Khachanov finished with a 17-8 edge in aces and won 81 percent of his first-serve points (30 of 37).
The only other seeded player in action Wednesday, No. 6 Marin Cilic of Croatia, topped the United States' Tommy Paul 7-5, 6-3 in the second round. Australia's John Millman also moved on to the quarterfinals by defeating Ukrainian qualifier Illya Marchenko 6-1, 5-7, 6-4.
In the last two first-round matches, Argentina's Federico Coria got past Russia's Alibek Kachmazov 6-2, 5-7, 6-2, and the United States' Mackenzie McDonald ousted Japan's Yoshihito Nishioka 6-3, 6-4.
Top-seeded Jan Sinner easily prevailed in an all-Italian second-round match at Antwerp, Belgium, defeating Lorenzo Musetti 7-5, 6-2.
Sinner faced just one break point in the match, and he won despite putting only 47 percent of his first serves in play.
Sinner's quarterfinal opponent will be France's Arthur Rinderknech, who upset eighth-seeded Serbian Dusan Lajovic 6-3, 4-6, 6-2.
Another quarterfinal matchup will feature U.S. qualifier Jenson Brooksby, a 6-2, 6-0 victor over the Netherlands' Botic Van de Zandschulp, and Spain's Alejandro Davidovich Fokina, who upset third-seeded Chilean Cristian Garin 4-6, 6-3, 6-3.
--Field Level Media