He and British partner Luke Bambridge were beaten by American duo Mackenzie McDonald and Christopher Eubanks 6-3 6-2 in the men's double in New York this morning.
An early break gave McDonald/Eubanks a lead which they held to claim the first set.
They followed that with two breaks through the middle of the second set to cruise to a comfortable win.
Errors hindered McLachlan/Bambridge.
They had 17 unforced errors to their opponents six, while they landed just 53% of their first serves and had seven double faults.
In contrast McDonald/Eubanks had an 84% first serve success rate.