ATP roundup: Tommy Paul, Aleksandar Kovacevic make Hamburg semis

Americans will comprise half the semifinals of the Hamburg Open, as No. 6 seed Tommy Paul defeated Germany's Daniel Altmaier 6-2, 7-5, and lucky loser Aleksandar Kovacevic extended his run in a three-set win over Argentina's Camilo Ugo Carabelli on Thursday.

One day after upsetting top-seeded Felix Auger-Aliassime of Canada, Kovacevic outlasted Ugo Carabelli 6-4, 6-7 (10), 6-2 in two hours and 43 minutes. The marathon second-set tiebreaker featured Ugo Carabelli saving one match point on his way to forcing the third set. But Kovacevic finished with nine aces and a perfect 7-for-7 mark in saving break points.

Kovacevic will face Peruvian qualifier Ignacio Buse, who topped Frenchman Ugo Humbert 6-3, 5-7, 6-3. Paul, seeking his second tournament title of the year, will square off with Australian third seed Alex de Minaur, who breezed past Italian seventh seed Luciano Darderi 6-0, 6-3.

Geneva Open

No. 2 seed Alexander Bublik of Kazakhstan and No. 4 seed Learner Tien will collide in the semifinals after each won three-setters in Switzerland.

Bublik absorbed 16 aces by French fifth seed Arthur Rinderknech and still prevailed 5-7, 6-4, 6-2. Tien battled past fellow American Alex Michelsen 6-4, 3-6, 6-1, saving 6 of 11 break points while converting all seven of his opportunities to break Michelsen.

The other semifinal match will see No. 6 seed Casper Ruud of Norway face Argentina's Mariano Navone. Ruud eased past Australia's Alexei Popyrin 6-4, 6-3, while Navone upset No. 8 seed Jaume Munar of Spain 6-2, 6-2.

--Field Level Media