This one was a long time coming for Jelena Jankovic. She had gone three-and-a-half years since last scoring a win over a WTA Top 4 player—that, despite Jankovic herself having been the year-end No. 1 in the not-too-distant past (2008).

And for a while today in Jankovic’s round-robin clash at the WTA Championships, it looked as if that long-awaited big win would be deferred yet again. World No. 2 Victoria Azarenka alternated some sloppy, tired-looking play with Houdini-esque escapes throughout this absorbing tussle, and managed to fend off all but four of 17 break points. And while Jankovic never trailed, and ended up winning 6-4, 6-3 in an hour and 49 minutes, the match was much closer than those numbers suggest.

For Jankovic, merely qualifying for the elite eight who contest the Championships was victory enough in this year of resurgence. But her confidence appears to be soaring, as she demonstrated by refusing to allow all those missed opportunities against Azarenka’s serve work on her mind and ultimately undermine her confidence—a process with which Jankovic is all too familiar. The real key to this match, more than Azarenka’s sometimes slovenly play or the glories of Jankovic’s down-the-line backhand, was the Serb’s ability to bounce back and hold serve after wasting, or being denied, so many opportunities.

Jankovic’s two most critical holds came after break chances evaporated in the close air of the indoor arena. In the ninth game of the first set, leading by just 5-3, Jankovic was unable to capitalize (through no fault of her own) on two set points. Azarenka held that service game from 15-40 down with four straight winners—enough to rattle anyone.

But Jankovic responded with a strong hold, aided significantly by the two sloppy forehand errors Azarenka made at the start of that 10th game, to win the set 6-4.

In the second set, Jankovic was a break up at 3-1 when an Azarenka double fault (her third of the match) put her in harm’s way at 15-40. She battled out of the fix with a pair of her patented forehand drive volley winners. But five deuces would follow, with Azarenka failing to convert hold points while playing like a demon to fend off break points.

Jankovic had six break points in the game, but had to settle for nothing as Azarenka come up with a valiant hold. That made it 3-2, with Jankovic to serve to improve her lead.

At that point, Jankovic skeptics as well as Azarenka fans could be forgiven for expecting Vika to punch through and turn the match around—JJ simply had not been able to put her away. Azarenka’s game was bound to improve, her confidence boosted by yet another magical escape act.

But Jankovic stepped up and held serve quickly, losing but one point and building her second-set lead to 4-2. Azarenka responded with a strong hold of her own, but Jankovic managed another one in the next game, thanks partly to her finishing shot at 40-15, an excellent second serve that stretched Azarenka so wide to the forehand side that she was unable to get good string on the ball.

Given the degree to which these women traditionally enjoy feasting on each others’ serves—in Cincinnati this summer, they combined for 23 breaks and four holds—and how big a relative weakness the serve of each one is in her overall game, it’s surprising that the match produced so many holds, especially from Jankovic. Who would have thought after the first set yielded three breaks in the first five games (two against Azarenka) that Jankovic would hold serve the rest of the way, and offer only two break points to the favorite after those first few games?

But that’s how the match ended, and it leaves two questions in its wake. Is the Jankovic resurgence for real and, second, will Azarenka emerge from the fog she’s been in since the end of the U.S. Open to fulfill her role as the group favorite in Istanbul?