Doha - Only two seeds remain at the Qatar Open after two more were beaten in the tournament's early matches on Wednesday, leaving six of the event's eight highest-ranked players out with only half of the second round completed.
Spain's Fernando Verdasco and Feliciano Lopez were the latest high-profile victims to join the growing list of seeds to fall early in Doha.
Russia's Andrey Rublev, 20, beat veteran seventh seed Verdasco in three sets, 6-4, 3-6, 6-4 in a centre court match watched by Qatar's Emir Sheikh Tamim bin Hamad Al-Thani and Paris Saint-Germain president Nasser al-Khelaifi.
The high-profile pair are former tennis partners and Khelaifi is also president of the Qatar Tennis Federation.
Rublev, the world number 39, broke Verdasco in the ninth game of the final set and needed one just match point to secure victory.
Earlier, wildcard world number 138 Mirza Basic shocked eighth seed Lopez with a straight sets victory 6-4, 7-6 (7/2).
Lopez is ranked 102 places higher than the Bosnian in the world standings.
The defeated Spaniards join the four seeds beaten in the first round, with second seed Pablo Carreno Busta, as well as Tomas Berdych, Albert Ramos-Vinolas and Filip Krajinovic -- numbers three, four and six respectively -- all falling at the first hurdle.
It means the tournament has already lost most of its top-ranked players after having being shorn of three major stars before it began, with Novak Djokovic, Stan Wawrinka and Jo-Wilfried Tsonga pulling out as they try to recover from injuries.
Only number one seed, world number five Dominic Thiem, and fifth seed Richard Gasquet remain, and both play later on Wednesday.
Austrian Thiem's second round match is against Slovenia's Aljaz Bedene while Frenchman Gasquet meets Greek qualifier Stefanos Tsitsipas.
Both are in the same side of the draw, which means an unseeded player is guaranteed to make Saturday's final in Doha.
That may provide an opportunity for one of the game's emerging stars to shine, such as Rublev or the man he will play in the quarter-finals, Borna Coric.
Croatian Coric, 21, followed up his impressive first round victory over Carreno Busta by easily dealing with blustery conditions on an outside court as he romped to a straight sets 6-1, 6-3 win over Nikoloz Basilashvili on Wednesday, his first tour win over the Georgian.
The world ranked number 48, who beat Andy Murray last year at the Madrid Open, had previously lost twice to Basilashvili, in Lyon and Cincinnati last year.