Milos Raonic moved closer to a second Citi Open title in Washington by defeating veteran Marcos Baghdatis on Thursday.
The third seed saved two set points on the way to a 7-6 (9-7) 6-4 win which makes sure of a quarter-final against Jack Sock.
Eighth seed Sock also saved two set points in his all-American match against Jared Donaldson, which he eventually won 7-6 (8-6) 6-2.
Top seed Dominic Thiem bowed out 6-3 6-7 (6-8) 7-6 (9-7) to Kevin Anderson in a contest which lasted two hours and 46 minutes.
Next up for the South African is Indian qualifier Yuki Bhambri, whose impressive run continued with a 6-7 (5-7) 6-3 6-1 defeat of Argentina’s Guido Pella.
Russia’s Daniil Medvedev defeated Bulgaria’s Grigor Dimitrov 6-4 6-2 and will face Alexander Zverev for a place in the last four after the German’s 7-5 7-5 defeat of American Tennys Sandgren.
Tommy Paul beat Gilles Muller 6-7 (3-7) 6-4 6-3 and will next face Kei Nishikori, who won 6-4 7-5 against Juan Martin del Potro.
Top seed Tomas Berdych had to work hard to reach the last four of the Abierto Mexicano in Los Cabos on Thursday.
The Czech lost the first set to France’s Adrian Mannarino and was also a break down in the decider – but he beat the No 7 seed 4-6 6-3 6-4.
It set up a semi-final against Thanasi Kokkinakis, the Australian wildcard who came through 7-6 (7-5) 6-2 against American Taylor Fritz.
Things were more straightforward for second seed Sam Querrey, who defeated France’s Vincent Millot 6-1 6-3 to book a semi against Damir Dzumhur.
The Bosnian beat fourth seed Feliciano Lopez 6-7 (2-7) 6-4 7-6 (7-2) in a hard-fought quarter-final.
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