Dustin Brown upset the odds to dump Gilles Simon out in the Open Sud de France second round, while Benoit Paire was also sent packing on Thursday.
Third seed Simon was playing his first match since an agonising five-set defeat to Novak Djokovic in the fourth round of the Australian Open.
But the Frenchman - ranked some 83 places above Brown in the world rankings - dipped below his usual standards in Montpellier and was knocked out in a 6-4 6-4 loss in a match that lasted little over an hour.
Home favourite Simon struggled to make inroads on Brown's serve, and the German - who knocked Rafael Nadal out of Wimbledon last year - dispatched two of six break-point chances he earned to progress to the quarter-finals.
Brown will meet Ruben Bemelmans in the last eight after the Belgian was a 6-4 6-7 (5-7) 6-3 victor over Jan-Lennard Struff.
Simon's fellow Frenchman and fourth seed Paire suffered a similar fate as the 2013 runner-up fell to a 6-3 6-3 loss to compatriot Paul-Henri Mathieu.
Mathieu now faces John Millman, who overcame Edouard Roger-Vasselin 4-6 6-1 6-4.