Grigor Dimitrov
This may not have been the most surprising upset considering that Dimitrov has not had much form lately, but the Bulgarian player had an excellent outing at the 2017 Australian Open, which may have given his fans some hope.
That said, the 11th seed took a couple of early wins before his Round of 32 exit to Pablo Carreno Busta, who has progressed to the quarters.
Carreno-Busta won 4-6, 7-6(2), 6-7(8), 6-4, 8-6.