Kyle Edmund fought back to claim his first Wimbledon win and end the hopes of fellow Briton and world number 869 Alex Ward.
Edmund, ranked 50th, won 4-6 6-3 6-2 6-1 on court three to reach the second round for the first time - at the fifth time of asking.
Ward, 27, had come through qualifying to take his place in the main draw.
Edmund, 22, goes on to face French 15th seed Gael Monfils or Daniel Brands of Germany in round two.
Fellow Britons James Ward, Brydan Klein and Katie Boulter are in action later on day two, after Andy Murray, Aljaz Bedene, Johanna Konta and Heather Watson all won on Monday.