Hull had to settle for a goalless draw on their competitive European debut as Tom Huddlestone missed a penalty and a point-blank follow-up against Slovakia's AS Trencin.
The Tigers, having qualified for a first ever campaign at Europa League level by finishing runners-up in the FA Cup, should have come away from their third qualifying round first leg at Zilina's Stadion pod Dubnom with victory but will now need a result in East Yorkshire next Thursday.
An hour had gone when Shane Long was felled in the area but Huddlestone - who missed in the shootout when Spurs lost to Basel in the 2013 competition - produced a dreadful double miss.
His penalty was comfortably saved by Milos Volesak but it was the secondary attempt, grazing the bar from a couple of yards with the goal yawning, that will haunt the midfielder.
Hull boss Steve Bruce started with a familiar looking side, each of the 11 starters having played their part in taking the club into Europe.
Two new arrivals, Robert Snodgrass and Tom Ince, bided their time on the bench, eventually getting 25 minutes under their belts in a double change.
Hull's evening almost got off to a perfect start inside two minutes when David Meyler won a free-kick and went close to converting Huddlestone's delivery at the back post.
The Tigers saw more of the ball in the opening half-hour but were kept at bay with relative comfort.
Their favoured route appeared to be crosses into the box and Meyler missed a half-chance before Long had a better opening laid on by the busy Liam Rosenior.
The Irishman was in a good position but could not keep his header down.
The momentum shifted in the 15 minutes before the break, Moses Simon and Patrik Misak beginning to threaten, but Hull's defence held out.
Alex Bruce, in particular, needed to be alert to dispossess Simon as he dribbled into the box, while Allan McGregor was left untroubled by Haris Hajradinovic's left-footed effort.
Trencin upped the ante eight minutes into the second half, Misak going desperately close with a long-range shot that just missed the target.
Long then made what should have been a decisive contribution, cutting inside the box only to be fouled by Peter Cogley.
Huddlestone's spot-kick was saved by Volesak but the rebound fell perfectly, presenting a straighforward finish for the former Spurs man.
But Huddlestone somehow contrived to flash his shot against the crossbar and high into the stands.
That moment knocked the wind out of Hull, with Bruce sending on his prize summer signings Ince and Snodgrass in response.
They could not change the result, but City will nevertheless head to the KC Stadium next week as favourites to reach the play-offs.