GSTAAD, Switzerland - Eugenie Bouchard stuck to her guns to make her first quarterfinal since February at the Ladies Championship Gstaad, saving seven set points in total and coming from a double break down in both sets with aggressive hitting to upset No.8 seed Viktorija Golubic 7-6(2), 7-6(7).

It was this willingness to battle that the Canadian, who was dissatisfied with the level of her game, emphasized afterwards. "I don't even think I'm playing that great," she said. "Conditions are tough - but I'm just trying to fight. That's what helped me out."

Bouchard improves her win-loss record at WTA main draw level in 2018 to 6-6, and to 14-10 overall, with the result - her first showing in the last eight of any tournament since defeating Zhu Lin and Ana Bogdan in Taipei City nearly six months ago. Having begun working with new coach Robert Lansdorp this spring, Bouchard has now won multiple matches at three of her last four tournaments.

Read more: 'I feel I can help her get better,' says Bouchard's new coach Robert Lansdorp

Initially, though, Bouchard seemed undone by the home favorite's style and variety. Golubic broke in the third game with the first of many delectable dropshots, and as she built up a 5-2 lead continued to yank the World No.146 around the court, to anticipate the direction of her full-bore groundstrokes and to find clever openings for her own softer shots to land as winners. The Swiss player also delighted with her rare one-handed backhand, particularly when she hit out on the stroke to find some glorious angles.

Viktorija Golubic prepares to unleash a one-handed backhand against Eugenie Bouchard at the 2018 Ladies Championship Gstaad (Robert Hradil/RvS Media)

But as the 2016 champion neared the end of the set, the outcome began to turn gradually in Bouchard's favor via a sequence of knife-edge games. Having emerged from a tight tussle to seal the double break on her fifth opportunity, mistakes began to creep into Golubic's game: one double fault as the 25-year-old served for the set for the first time, two more the second time round and another one in the ensuing tiebreak, plus a simple forehand putaway into the net on the first of two set points on return.

Bouchard, stubbornly sticking to her favored strategy of aggressive returns, was still hit-or-miss, and showed her frustration with a toss of the racket after going all out on a forehand off a slow, loopy Golubic shot - and missing. Increasingly, though, going for her shots no matter what paid off. A scorching backhand return sealed the first break back; strong serving and all-out power were key to dominating the tiebreak.

But just as some more ferocious returning sent Bouchard up a break in the second set, the tide began to turn again. This time, it was the 24-year-old who was afflicted by double faults: having hit none in the first set, she would commit at least one in each of her subsequent service games - including when facing break point in both the second and sixth games.

Having been handed a way back into the match, Golubic's confidence rose again, and the World No.110 seemed in command as she held for 5-2 with a clean dropshot winner - and then made her way to triple set point in the next game with a neat volley putaway.

Eugenie Bouchard powers through a backhand against Viktorija Golubic at the 2018 Ladies Championship Gstaad (Robert Hradil/RvS Media)

Bouchard's battling qualities would characterize her performance today, though, and just as in the first set, staring down the barrel of defeat seemed to focus her mind. A dropshot of her own and a brace of unreturnable serves staved off danger in this game; Golubic would reach double set point on her own serve in the next, but those would flash past too, one with a netted backhand from the Swiss and the second with another punishing, deep Bouchard return.

If anything, the start of the day's second tiebreak was even more one-sided than the first as the 2014 Wimbledon runner-up stormed to a 6-1 lead, with Golubic hardly able to get a return of serve in play. A series of impatient errors from Bouchard and careful point construction from Golubic saw all five evaporate just as quickly, though.

Afterwards, Bouchard would point out that dramatic fluctuations are par for the course in tennis. "It happens all the time - people are up and then lose, or whatever - so I just tried to remain calm," she said.

This once again helped her stay firm in the face of danger - this time holding back and letting her opponent, with a lifeline suddenly in reach, hit herself out of the match again. A Golubic forehand shank on Bouchard's seventh match point would send the Canadian through to the last eight, where she will face the fast-rising Russian qualifier Veronika Kudermetova, who also scored an upset in two tiebreak sets, 7-6(4), 7-6(5) over No.3 seed Viktoria Kuzmova.