Southampton elevated themselves to third in the Premier League standings and extended their unbeaten run to eight matches.
Goals from Morgan Schneiderlin, Rickie Lambert and Adam Lallana gave the hosts a 3-0 lead at the break before Yannick Sagbo gave Bruce's men hope, until Steven Davis slotted home Southampton's fourth to seal victory.
Defeat means Hull have lost five of their last six games on the road but Bruce admits he knew a visit to St Mary's would provide a stern test.
"I knew they were a very good side," he told Sky Sports. "The DVDs we've been watching have proved that.
"A return of 19 points before today is a marvellous return and a performance like that you can see exactly why they have got to the top of the league.
"It's good times if you're a Southampton fan because they have a very, very good side, apart from the obvious ones we know Southampton will be a match for anybody."
As Saints entered the break with a three-goal advantage, Bruce opted to switch his 5-3-1-1 formation to 4-4-2 with the introduction of Robert Koren at half-time and conceded he should have started the way he finished.
"You can talk about tactics, formations and systems and ours worked perfectly well against Tottenham two weeks ago and we thought we'd go that way again," he reflected.
"In hindsight I wish I'd have gone with a back four, we can all say that.
"You can say what you like about systems but sometimes you just have to say well done to the opposition, today they were the better team by a million miles.
"We didn't get beat in the second half, the first half we were close to getting blown away but they stuck at it.
"I expected them to stick at it and who knows, if we'd have got the second goal we may have made a bigger fist of it. Overall today, we were just beaten by a far better team than us."
Goalscorers Lambert and Lallana were both called into the England squad by Roy Hodgson earlier in the week, as was Saints striker Jay Rodriguez and Bruce paid homage Southampton's renowned academy system.
"You have to pay them a compliment, their academy has produced some fantastic players in the last four, five years," he added.
"To produce a player like Lallana, who has everything in his feet, you can see why three of them are in the England squad.
"When a club of Southampton's size has three players in the England squad, they must be doing things right.
"A big pat on the back to them, I went to watch Lallana four, five years ago when the team were in division one and since then they've made huge progress."