The fifth seed was utterly dominant as he brushed past his opponent in what proved to be a first-round win of consummate ease.
Tomic, the world number 28, took the opening set with a couple of impressive breaks of serve as he pinned Lacko back behind the baseline.
The second set was no easier for the world number 63 as the Slovak failed to make a real impression with an early break of serve leaving him under the cosh.
Tomic won through with a composed finish, and the Australian will next take on Kazakhstan's
The world number 42 justified his seeding as he took the tie-break 7-3 in convincing fashion after being tested in the opening set.
But Falla responded in style with a crushing display of power-hitting in the second set, taking it 6-1 and leaving his opponent utterly stunned.
Istomin was not to be denied, however, and he replied with a reversed scoreline in the third and final set.
The Uzbek will next take on
Fognini faltered badly in the opening set tie-break as the world number 61 Darcis stamped his authority on the match.
The Italian remained in contention at 5-5 in the second set, but Darcis again came through in clinical fashion to take it with a solitary break of serve.
Darcis will next face
In other first-round matches, Brazil's
Bellucci next faces
Dimtrov is rewarded with a second-round match against