Steve Bruce promised jubilant supporters their Hull team would be "better next time" after the Tigers won through to the Europa League play-offs in dramatic fashion.
Hull will find out on Friday morning who they face in a two-legged battle to reach the group stages following their 2-1 victory over plucky Slovakian club AS Trencin.
It looked like the visitors would progress after they scored an early away goal through Tomas Malec, but Ahmed Elmohamady levelled with a header on the half-hour mark.
With time running out the natives began to get restless, fearing loss on the away goals rule, until substitute Sone Aluko sent them into raptures with a winning volley 10 minutes from the final whistle.
Tigers boss Bruce said: "I'm pleased for the supporters in particular.
"Coaches, managers, owners, chairmen, they come and go, but the only thing a football club needs more than anything is its supporters and the people of Hull.
"I'm delighted to see a full house. A guy came up to me before the game and said 'I never thought I'd see the day we'd be playing in a European cup', which is fabulous.
"Let's see where we end up next time. And we'll be better next time."
For a long time Bruce thought the club's maiden European adventure was over before it had even begun.
"You're always worried when there's 15 minutes to go and you're thinking about all the hype and euphoria, but you're about to fall at the first hurdle," he said.
"But we've stuck at it and, not for the first time, we've seen them do it.
"It's been difficult but we've got through it and let's enjoy the draw tomorrow."
Trencin had no intentions of rolling over, or sitting back once they had taken a shock lead, and strikers Shane Long and Yannick Sagbo both failed to provide sufficient bite in the quest for a comeback.
And Bruce has warned his players they need to start putting their chances away against the heavyweights of Europe.
"I think that's the biggest lesson," he added. "Playing in the Premier League's the same, and when you play in Europe you don't get that many.
"To be fair we've missed three or four glorious chances and thought we weren't going to get it.
"We made an awful start and that put everyone on edge for 20 minutes, not just the players, but the crowd, who I think were fantastic.
"There was a frustration there but thankfully we've seen it through."
While Bruce watched victory being snatched from the jaws of defeat, the experience of Trencin boss Martin Sevela was the exact opposite.
He said: "We are very sad that we didn't go through. We were 10 minutes from the end - and from victory.
"We started the game very well, scored the goal, had great chances and were dangerous.
"It took them a little while to get themselves together after we scored but they were physically very well prepared and I would like to congratulate Hull City for going further.
"I wish them all the best and I hope they get to the Europa League (group stages) and do well."