While three ATP tournaments are being staged this week, only one of the events still boasts its top seed.

A day after Sardinia's highest seeded player, Fabio Fognini, was withdrawn as a result of testing positive for COVID-19, Daniil Medvedev—the No. 1 seed in St. Petersburg—saw his title defense come to a crashing halt on Thursday.

Reilly Opelka battled back to win, 2-6, 7-5, 6-4, in one hour and 55 minutes. Opelka capitalized in the crucial moments by breaking at the end of the second and third sets to oust the world No. 6. Medvedev missed four break point opportunities in the deciding set, and has now lost four of his past five matches since reaching the semifinals of the US Open.

For Opelka, he’s now 6-6 lifetime against Top 10 opposition and 2-2 this year, adding to his third-round win at ‘Cincinnati in New York’ over No. 8 Matteo Berrettini. In Friday’s quarterfinals, the American will take on No. 7 seed Borna Coric, a 6-3, 7-5 winner over wild card Roman Safiullin. Coric finished runner-up to Medevdev at the indoor hard-court event last year.

Opelka ousts Medvedev in St. Petersburg; Zverev takes Cologne opener

Opelka ousts Medvedev in St. Petersburg; Zverev takes Cologne opener


AP and Getty Images

Second seed Denis Shapovalov set an intriguing quarterfinal clash with No. 5 seed Stan Wawrinka. The Canadian brushed aside qualifier Ilya Ivashka, 6-1, 6-4, saving all five break points he faced. He and Wawrinka have split their two prior meetings, which also took place on indoor hard. Third seed Andrey Rublev, making his Top 10 debut this week, edged Ugo Humbert, 4-6, 6-4, 7-5, after two hours and 14 minutes. Another left-hander, Cam Norrie, awaits the world No. 10.

In Cologne, No. 1 seed Alexander Zverev won his opener without much resistance thanks to a steady day on serve. The US Open finalist eased past Fernando Verdasco, 6-4, 6-1, by winning 84 percent of his service points and hitting seven aces to zero double faults.

This marked Zverev’s first appearance since revealing he had a fever in Paris following a fourth-round defeat to Jannik Sinner at Roland Garros. For a place in the semifinals, Zverev will face Lloyd Harris, who advanced past Steve Johnson Wednesday evening.

In other action, No. 3 seed Felix Auger-Aliassime did not face a break point en route to defeating qualifier Henri Laaksonen, 6-4, 6-1. Alejandro Davidovich Fokina erased a set and a break deficit to knock out eighth seed Marin Cilic, 3-6, 7-6 (3), 6-2.

Two more seeds in Sardinia were sent packing, leaving Albert Ramos-Vinolas as the only one of the eight to get through to the quarterfinals. Seeded fourth, Ramos-Vinolas dispatched Corentin Moutet, 6-0, 6-3, but Casper Ruud, the No. 3 seed and Tommy Paul, the No. 7 seed, were eliminated in straight sets by Yannick Hanfmann and Marco Cecchinato, respectively.

Hanfmann will square off against rising 18-year-old Lorenzo Musetti, who advanced to his first tour-level quarterfinal. The wild card routed countryman Andrea Pellegrino, 6-2, 6-1, to end the qualifier's bid.