The Bosnian frontman's 89th-minute strike leaves Bruno Labbadia's side, who have also lost their opening two Bundesliga matches, now requiring just a 1-0 victory in next Thursday's return leg at the Mercedes-Benz Arena to progress.
Harnik goes close
The contest got off to a hectic start in the small-scale but atmospheric Kantrida Stadium and the vociferous home crowd almost had something to cheer in the sixth minute when Leon Benko found himself through one-on-one on Sven Ulreich, but the VfB keeper pulled off a great reflex save to foil the one-time 1. FC Nürnberg forward.
HNK custodian Ivan Vargic was in action for the first time not long after that, punching away an effort from Cacau, and in the period that followed the Bundesliga visitors enjoyed more than their share of possession. They had little luck in finding the vital defence-opening pass that would trouble their opponents, however, until the 28th minute, when Martin Harnik clipped the post with a shot from outside the box.
Late drama at both ends
The second half began with Benko just failing to connect with a cross that would surely have led to the breakthrough goal for the hosts. That was as exciting as it got at either end for quite some time in an increasingly scrappy contest and with 20 minutes to go, Labbadia introduced Alexandru Maxim to try and inject fresh life into his stuttering forward line. Two minutes later, Harnik stabbed the ball into the net, but the effort was ruled offside. Benko's strike on the back of it passed muster, though, the forward shrugging of Daniel Schwaab to nod home Tomecak's cross unchallenged.
VfB finally got their frontline act going in response, Harnik pulling a good save out of Vargic and Ibisevic drilling a header over from the resultant corner. Maxim, teed up by Harnik, was then brilliantly foiled by Vargic at close-range and with the clock rapidly ticking down it was the hosts, instead, who found the net again, Benko turning provider for Zoran Kvrzic to coolly slot home. It was looking distinctly bleak for Stuttgart now, but Ibisevic made the return a whole different ball game when he snaffled up Christian Gentner's cross-shot with a minute of regulation time remaining.
Rijeka: Vargic - Tomecak, Leskovic, Maric, Skarabot (Boras) - Males - Zlomislic, Alispahic (Pokrivac 69'), Anas Sharbini (Mocinic 61'), Kvrzic - Bento
Stuttgart: Ulreich - Sakai, Schwaab, Rüdiger, Molinaro - Boka, Gentner - Harnik (Abdellaoue 84'), Leitner - Cacau (Maxim 69'), Ibisevic
Goals: 1-0 Benko (74'), 2-0 Kvrzic (87'), 2-1 Ibisevic (89')