"I cannot play anymore, so that's why I'm pulling out. I'm tired and I have problems with my leg," the Romanian told press following a grueling three-set win over Sabine Lisicki. Halep had been using mixed as a practice for her singles - and perhaps to test the waters of an Olympic entry with her countryman - but with a quarterfinal encounter with two-time US Open finalist Victoria Azarenka looming, a tough choice had to be made.
"Horia understood. Not nice, but it's never nice when you pull out."
Halep visibly enjoyed her two wins with Tecau, and certainly didn't rule out a return to the co-ed competition come 2016.
"It was a fun, fun experience here."
The walkover is the second for Hingis and Paes this week; with the Swiss Miss still alive in women's doubles with Sania Mirza, an extra push towards a third mixed doubles major of the season must feel like a much-needed gift as the US Open heads into the final stretch.
Up next for the dynamic duo is No.2 seed Chan Yung-Jan, who won another long match with partner Rohanna Bopanna against two-time major doubles champion Hsieh Su-wei and her partner, Henri Kontinen, 7-6(7), 5-7, 13-11 in the super-tiebreak. Chan is also slated to play Hingis on Tuesday alongside sister Hao-Ching in the quarterfinals of women's doubles.
Earier in the day, No.12 seeds Alla Kudryavtseva and Anastasia Pavlyuchenkova reached their first Grand Slam quarterfinal as a pair, surviving a second set lull to dispatch No.17 seeds Karin Knapp and 2012 champion Roberta Vinci, 7-6(2), 2-6, 6-2. Kudryavtseva is coming off an outstanding summer with Mylan World TeamTennis; playing for the Austin Aces, the Russian was named Rookie of the Year as she led the Aces into the championship match against the Washington Kastles - a team achored by Hingis and Paes. Elsewhere, Kristina Mladenovic couldn't replicate her singles heroics with fellow No.3 seed Timea Babos, losing to No.15 seeds Lara Arruabarrena and Andreja Klepac, 6-4, 4-6, 6-4.