The Tigers, favourites for the Division Three title, more than lived up to expectations with a comfortable success.
Ben Burgess put Hull ahead when he headed home Jason Price's cross.
Hull secured victory with just eight minutes remaining when new signing Danny Allsopp pounced to complete a poor night for Peter Reid.
One plus point for Leeds was the return to action of injury plagued striker Michael Bridges.
Newcastle had a very strange evening with one dominant display and another which saw them suffer a shock defeat.
The first side led by John Carver at Hartlepool's Victoria Park romped to a 6-0 success, while the second team went down 4-3 at Sheffield Wednesday.
The team on Teesside was led by Alan Shearer and the Magpies skipper looked in remarkably good form - helping himself to a first half hat-trick after Craig Bellamy had already put Newcastle ahead.
After the interval United added two more through Gary Speed and Nolberto Solano to secure victory.
The Magpies` second team - which included the likes Kieron Dyer, Lee Bowyer, Titus Bramble, Andy O'Brien and Aaron Hughes - could not match their team-mates at Hartlepool.
Lloyd Owusu put The Owls ahead after just two minutes, but captain for the night Dyer levelled matters after 20 minutes.
Shola Ameobi put Newcastle ahead just a minute into the second half before Tresor Lomana Lua Lua added a third.
Wednesday, though, continued to fight hard and new captain Dean Smith headed home to reduce the arrears.
Craig Armstrong levelled matters for the home side on 77 and then two minutes later Finnish star Shefki Kuqi volleyed home a wonderful winner to embarrass Sir Bobby Robson's side.
A strong Middlesbrough reserve side lost out to Grimsby Town in a behind-closed doors friendly at Blundell Park with
Cardiff City showed their capabilities with a 2-1 win over Charlton Athletic at Ninian Park.
Jonatan Johansson had given The Addicks a half time lead after putting his side ahead after 20 minutes.
But Cardiff came back strong in the second period and former Middlesbrough duo Graham Kavanagh (56) and Andrew Campbell (80) secured victory for Lennie Lawrence's side.
Southampton continued their good pre-seeason with a hard fought 3-2 win at Reading.
James Beattie and Fabrice Fernandes gave The Sainst a half time lead, but The Royals got themesleves back into the game with a Nicky Shorey penalty.
However, Matthew Oakey grabbed the winner for Southampton with a spectacular effort, before Darius Henderson pulled back a consolation for the home side.
