The 25-year-old won his opening-round doubles match alongside German Jan-Lennard Struff, beating Australian duo Thanasi Kokkinakis and Jordan Thompson 6-4, 6-3.
It was a cleaner performance from the winning pair who had no double faults, compared with their opponents' eight. They converted four of five break points and saved five themselves.
Alongside that, they hit 26 winners, compared with the 10 the Australian duo managed.
It was at 3-3 in the first set that McLachlan and Struff made the key move after each combination had dropped serve once.
At deuce, a double fault from their opponents gave McLachlan and Struff the advantage, before a forehand winner put them up 4-3.
A tense final game of the set ensued at 5-4 as an 11-minute, 22-point grind ended with a forced backhand error from the Australians, allowing McLachlan and Struff to go one-up.
In the second set, the winners took their opportunities, while the losing duo failed to take theirs.
McLachlan and Struff had just two break points, but were able to claim both, proving the difference as they won the set 6-3. The Australian duo failed to capitalise on any of their three.
McLachlan and Struff will meet Spanish duo Feliciano Lopez and Marc Lopez in the second round.
It will be a major step up for McLachlan, who is ranked 73rd in the world. The Spanish duo are both ranked inside the world's top 25.
However, McLachlan has proven his ability against this calibre before. In winning the Japan Open, shortly after switching national allegiances last year, he downed two former grand slam-winning duos.
There were 64 pairs in the men's doubles competition, with 32 remaining in the second round.
