Blow to tournament organisers as Vinci joins four other seeds to bow out.
Top seed Roberta Vinci crashed out of the ASB Classic in Auckland last night bringing to five the number of seeds to exit the tournament early.
The world No 14-ranked Italian lost her first round match to wildcard and world No 259 Ana Konjuh of Croatia 3-6, 6-4, 6-2 in one of the biggest upsets of the tournament.
Vinci looked on track to progress with a reasonably comfortable first set win but the wheels fell off with Konjuh growing in confidence to force the top seed into errors from which she never recovered.
Konjuh will now face little-known Lauren Davis today after the American made quick work of Kiwi hope Marina Erakovic 6-1, 6-4.
The way now seems clear for second seed Ana Ivanovic, although she too sent a scare through the organisers before advancing safely to the second round.
Ivanovic, one of the two jewels in the tournament's crown, overcame a tight shoulder and a tough opponent to win 7-5, 7-6 and set up an encounter with Johanna Larsson.
The former impediment was of a greater concern than American Alison Riske, with Ivanovic requiring the attention of the trainer midway through the second set. Fans and organisers watched anxiously as Ivanovic had strapping tape applied.
A withdrawal would have been a huge blow to the tournament but Ivanovic recovered to claim the match, later revealing that retiring never crossed her mind.
"No, not at all," she said. "It was really just tightness. It was just a bit gusty and there were a few times I had mis-hits and felt it a little bit, but it was just tightness so I'm going to do some recovery now.
"It's nothing serious and I'm playing doubles, too."
Indeed, with Ivanovic and Kirsten Flipkens advancing in Monday's first round, there will be at least a couple more sightings of the glamorous Serb on centre court.
And, judging by yesterday, the crowd at Stanley St will relish every one.
Ivanovic, the world No 16, showed her flair throughout the match, coming back from a break down in both sets and seeing off five set points before taking the second on a tie-break.
The 57th-ranked Riske had Ivanovic on the ropes at several points but failed to knock her to the canvas, with the former French Open winner leaning on a big serve even after the injury break.
"[Riske] played really well and aggressive and we had quite a few long rallies," Ivanovic said.
"I was very pleased with the way I came back and kept composed at the important moments. I was actually very happy to finish in two sets."
Ivanovic will tonight play the 84th-ranked Larsson.
Last year's beaten finalist Yanina Wickmayer was dumped by Kristyna Pliskova 7-6 (3) 6-0, fourth seed Sorana Cirstea lost to Sharon Fichman, sixth seed Lucie Safarova went down to Ayumi Morita, both in straight sets and eighth seed Karin Knapp was beaten in three sets by Julia Goerges. Third seed Flipkens avoided the trend to see off Monica Puig 6-4, 7-5.
World number 18, Tommy Robredo of Spain, has withdrawn from next week's Heineken Open with an arm injury.