Jack Sock came through a tough second-round clash with Elias Ymer to book a quarterfinal place at the Stockholm Open.
America's No. 4 seed was taken to a deciding set by home favourite Ymer, who was handed a wild card into the tournament.
Sock proved too strong in the final set, though, and advanced with a 7-5, 3-6, 6-3 win in Sweden on Wednesday.
Greece's Stefanos Tsitsipas saw off John Millman in a tight encounter to move into the last eight.
No. 3 seed Tsitsipas enjoyed a 6-4, 3-6, 6-3 win over the Australian Millman.
No. 7 seed Denis Shapovalov booked a place in the last 16 with a 6-3, 5-7, 7-5 triumph against fellow Canadian Peter Polansky. Elsewhere, qualifier Oscar Otte defeated lucky loser Jurgen Zopp 6-3, 7-5. No. 6 seed Hyeon Chung cruised past Denis Kudla with a 6-3, 6-3 win.