Top seed Dominic Thiem booked his place in the quarterfinals of the Qatar Open with a 7-5, 6-4 victory over Stefanos Tsitsipas.
Austria's Thiem had reached the last eight by ousting former Great Britain player Aljaz Bedene and was in equally-efficient mood on Thursday as he accounted for Greece's Tsitsipas.
Another big name in the final four in Doha is former world No. 6 Gael Monfils, who was a 6-3, 7-6 victor over Peter Gojowczyk.
Promising Russian youngster Andrey Rublev is also in the semifinals following his convincing 6-3, 7-5 win over Croatia's Borna Coric, while Argentina's Guido Pella eased past Bosnian qualifier Mirza Basic 6-2, 6-3.