Stockholm, Sweden, 22 October 2015 | AAP/AP

Bernard Tomic’s push for a top-15 ranking has stalled with a second-round loss to veteran Cypriot Marcos Baghdatis at the Stockholm Open.

Baghdatis upset Tomic 7-6(7) 6-3 on Wednesday, also spoiling the Australian No.1’s 23rd birthday celebrations.

Baghdatis admitted he used his “brain a lot” to outsmart the world No.18 in a blow to Tomic’s hopes of securing an all-important top-16 seeding for the Australian Open in January.

“You need to be smart on court and not hurry too much. I think I did it very well,” said Baghdatis, the Australian Open 2006 finalist now ranked 44th.

Tomic’s defeat also denied him a 10th quarterfinal berth of the year and came after fellow Australian John Millman also exited the tournament.

Luxembourg’s big-serving left-hander Gilles Muller fired 14 aces to see off Millman 7-5 6-3 in 76 minutes.

Meanwhile, at the Kremlin Cup in Moscow, Daria Gavrilova fell in straight sets to No.3 seed Flavia Pennetta.

Pennetta’s 6-2 6-4 victory confirmed the Italian’s qualification at next week’s elite eight-player WTA Finals in Singapore.