Top-seeded Marin Cilic saved three match points to narrowly avoid becoming the latest upset at the Memphis International tournament on Thursday.
Cilic avoided the same fate that befell second seed Milos Raonic on Wednesday despite trailing 6-4 and 7-6 in the third set tiebreak against Igor Sijsling, who double faulted on his third match point to allow Cilic to steal the tie-break 9-7 and set up a quarter-final against Japan's Kei Nishikori.
The Croat's recovery ensured he did not become the second seeded player in the men's draw to lose on Thursday after fourth seed Sam Querrey lost momentum in the second set of his match and was beaten 3-6, 6-4, 7-5 by Australia's Marinko Matosevic.
Women's top-seed Kirsten Flipkens was also knocked out, losing to Slovakia's Magdalena Rybarikova 6-7, 7-5, 6-2, a day after second seed Sofia Arvidsson crashed out in the second round.
Fourth seeded Briton Heather Watson was also beaten by Switzerland's Stefanie Voegele, though third seed Sabine Lisicki advanced past France's Kristina Mladenovic 6-3, 6-3.