United overcome plucky League Two side...
UNITED 3 (Nunez 46, McCormack 69, Nunez 75), BRADFORD CITY 2 (Compton 31, Flynn 57)
United: Lonergan, Connolly (Lees 72), O'Brien (Bromby 62), Kisnorbo, Parker,, Brown, Clayton, Sam, Howson, Nunez, McCormack (Taylor 90). Subs: Rachubka, Bruce, Thompson.
Bradford City: Jansson, Branston, Mitchell (Hannah 85), Threlfall, Moore, Flynn, Williams, Syers (Jones 63), Compton, Stewart (Rodney 78), J Hanson Subs: Oliver, McLaughlan, Wells, O'Brien.
Referee: C Webster
Bookings: Syers, Branston (Bradford)
United manager Simon Grayson made three enforced changes to the side which lost to Southampton on the opening day of the season and drafted in two youngsters to his subs bench.
Max Gradel, Robert Snodgrass, and Darren O'Dea were all away on international duty, prompting the inclusion of Lloyd Sam, Ramon Nunez and Ben Parker in the starting line-up. Zac Thompson and Charlie Taylor were the two youngsters on the bench, while Billy Paynter is an addition to the injury list and missed out.
There was a lively atmosphere inside the stadium, and the game started off at a frenetic pace. United had a couple of early raids and Bradford forced Andy Lonergan into making a save inside the opening 10 minutes.
There was also an early booking for Bradford's Dave Syers for a hefty challenge on Parker, and the visitors were clearly going to scrap and hassle for everything.
United put together the best passage of play so far on 20 minutes when Lloyd Sam whipped in a cross from the right and Adam Clayton's shot was over the top.
Clayton was also involved moments later when he beat the offside trap and crossed to create a good chance for Nunez, who lofted his effort over the bar.
United were starting to apply pressure and Nunez fired into the side netting on 27 minutes from a tight angle and more good play by Leeds.
But it was Bradford who went in front on 31 minutes. Mark Stewart did well down the left and pulled back for Jack Compton to convert from close range.
The goal rocked the Elland Road crowd and United had to re-group as the game headed towards the interval. In the final moment of the half Nunez had a shot deflected wide, but no corner was awarded.
Just 26 seconds into the second half United were level, though. Sam showed great feet inside the box, Clayton showed good awareness, and Nunez smashed home his first goal for the club to make it 1-1.
But Bradford threatened again when Syers seized on a loose ball and he drove his shot across the face of goal.
United immediately raced down the other end and McCormack beat the offside trap before drilling a shot wide.
The visitors went back in front on 57 minutes, though, with a goal of real quality. Robbie Threlfall played the ball into the box and Michael Flynn supplied a first time finish to stun Leeds.
Moments later, Syers found himself in the clear and bearing down on goal, but a poor touch gave Lonergan the opportunity to come out and deny the striker.
On 62 minutes, Grayson made a double change with Tom Lees and Leigh Bromby replacing Paul Connolly and Andy O'Brien at the back.
United were now having to rally and both McCormack and Nunez threatened, and it was the Scot who found an equaliser on 69 minutes when he latched on to a great cross from the right and headed home at the far post.
Less than five minutes later Leeds were in front for the first time. Sam got in a low cross, the Bradford keeper failed to deal with it, and Nunez was on hand to convert from close range.
The third goal appeared to knock the stuffing out of the plucky League Two side, and McCormack went close again as United pressed for another goal to put the game beyond doubt.
Clayton also tried his luck with a shot which stung the keeper's gloves before Guy Branston made an important block to deny McCormack. The Scot also brought about a good save and United were finishing the game strongly.
As the clock ticked down, Charlie Taylor joined Lees in the debut stakes when he replaced McCormack for the final three minutes of stoppage time.
Five minutes were added on, but United held firm to record progress in the competition by collecting a first win of the new season.