© Ben Solomon/Mubadala Citi DC Open

Mackenzie McDonald and Ben Shelton in action Thursday at the Mubadala Citi DC Open.

McDonald/Shelton Move Into Washington SFs

Wild cards will next meet third seeds Glasspool/Heliovaara

Americans Mackenzie McDonald and Ben Shelton survived a thrilling battle Thursday to reach the semi-finals at the Mubadala Citi DC Open.

The wild cards defeated Juan Sebastian Cabal and Matthew Ebden 6-4, 3-6, 10-8 after dropping just six points behind their first serve. McDonald and Shelton fought off seven of eight break points faced and despite winning 64 total points to Cabal and Ebden's 65, the American duo advanced to the last four, where they will meet third seeds Lloyd Glasspool and Harri Heliovaara.

At 7/7 in the Match Tie-break, the Washington crowd was brought to their feet when McDonald and Shelton won an exciting rally. The Americans displayed great defence before the 20-year-old Shelton sealed the point with a volley that pegged Cabal. Shelton celebrated the dramatic point by sprinting back to the baseline, high-fiving a fan along the way.

Cabal and Ebden were aiming to back up their opening-round upset against top seeds Rajeev Ram and Joe Salisbury.

Belgians Sander Gille and Joran Vliegen downed Jamie Murray and Michael Venus 7-6(4), 4-6, 10-8 to also advance to the ATP 500 semi-finals.

Third seeds Sadio Doumbia and Fabien Reboul ousted Guido Andreozzi and Guillermo Duran 7-6(5), 7-6(3) to book their semi-final ticket at the Generali Open.

Fourth seeds Gonzalo Escobar and Aleksandr Nedovyesov cruised past Romain Arneodo and Sam Weissborn 6-3, 6-2. The Colombian-Kazakh pair will next meet Francisco Cabral and Rafael Matos, who beat Simone Bolelli and Andrea Vavassori 7-6(3), 7-6(5).