Dominic Thiem is the only seeded player through to the quarter-finals of the Qatar Open.
Top seed Thiem progressed with a 7-5 6-4 win over Aljaz Bedene of Slovenia on a windy Wednesday in Doha.
The Austrian served up nine aces during the match, and successfully took advantage of three of the 15 break point opportunities presented.
"I'm pleased today I'm through in straight sets," Thiem said. "(I) had two tough matches which I won both in straight sets. So I think that's a perfect start into the new year.
"If you have to fight a lot, if you have to suffer a bit, I think it's very good like this."
Thiem will play 19-year-old Greek qualifier Stefano Tsitsipas in the quarter-finals.
The 91st-ranked Tsitsipas ended fifth-seeded Richard Gasquet's hopes of winning a second Qatar Open title with a 6-3 6-4 victory in the final match played on Wednesday.
Playing near perfect tennis, Tsitsipas never offered Gasquet a break point. He broke the Frenchman's serve in the sixth game of the first set and the seventh game of the second.
Unseeded Gael Monfils, a three-time finalist in Doha, beat Jan-Lennard Struff of Germany 6-3 1-6 6-3.
Monfils, who is playing his first tournament since retiring in the US Open third-round against Belgian David Goffin with a right knee injury, will play Peter Gojowczyk of Germany in the quarters.
Seventh-seeded Spaniard Fernando Verdasco was eliminated by 39th-ranked Andrey Rublev of Russia 6-4 3-6 6-4.
Serving at 5-4 in the final game of the third-set, Rublev saved two break points to move into the quarter-finals where he'll play Borna Coric of Croatia.
Eighth-seeded Feliciano Lopez of Spain fell to Bosnian qualifier Mirza Basic 6-4 7-6 (7-2) in a first career meeting.
Basic will play unseeded Guido Pella of Argentina in the other quarter-final.
