Halep had been a doubt for the tournament because of a back injury sustained in training and was not moving freely as she was on the wrong side of a first-set bagel. 

The No.1 seed was a bit more like her sprightly self in the second set after receiving treatment on her back and left thigh, but Cibulkova sealed a round-three meeting with Daria Kasatkina by winning 6-0 7-5.

It was past midnight when Cibulkova sent Halep packing after hitting 20 winners in a great display of intensity, improving her record over the French Open champion to five wins and just two defeats.

Halep, playing her first match since suffering a shock loss to Kaia Kenepi in the first round of the US Open, won only 37 per cent of points on first serve and was broken seven times to make another early exit at a tournament where she lost to Kasatkina at the same stage last year.

Cibulkova made a blistering start and did not let her standards slip in a first set which was over in a flash, Halep looping a forehand way beyond the baseline to go 2-0 down.

The Slovakian won 12 points in a row to lead 5-0, at which point Halep called for a first medical timeout, and sealed the bagel with a deft backhand drop shot. 

Halep, already assured of a place in the season-ending WTA Finals in Singapore, hit just one winner in the opening set and was a break down in the second after spraying a forehand wide. 

The Romanian finally got on the board with a break when Cibulkova netted a forehand, then further treatment seemed to do the trick as she moved into a 4-2 lead.

Cibulkova shifted the momentum, though, breaking three times in a row to avoid a third set, finishing it style with a rasping cross-court forehand winner to punish Halep for failing to put away an overhead volley in a brilliant final rally.