The Potters had 13 shots in the opening 45 minutes and continued to press forward in the second half, but were dealt a suckerpunch by Ulloa's 67th-minute strike.
Below, Sports Mole analyses whether the result was reflective of the action.
On target: 4
On target: 1
Was the result fair?
Stoke were mighty unfortunate not to at least draw, and Mark Hughes may not even have settled for that. They could have been two or three up by the break such was their superiority, and were still pressing forward when Ulloa put the visitors ahead against the run of play. Leicester had one shot on target, and Stoke 24 shots in total, with the decisive difference being that the Foxes have a finisher who seems to be capable of bagging 15 goals a season.
They did everything but score in a first half which they dominated due to their control of the midfield. Steven N'Zonzi and Glenn Whelan pushed up high to pin Leicester back and this helped Stoke apply constant pressure on the visitors. Peter Crouch proved to be a good focal point to the attack in the absence of Mame Biram Diouf, but the Potters were reluctant to use his aerial prowess too often, which may not have mattered, because the final ball from the flanks was inconsistent to say the least. Hughes has added pace and trickery to his side with the signings of Victor Moses and Bojan, but composure in terms of picking out crucial passes and making the most of their chances is still lacking. A second home defeat of the season already will come as a blow to the Stoke boss after their great result at Manchester City a fortnight ago.
They really struggled to cope with the numbers and pace in Stoke's midfield in the first half, with Andy King and Dean Hammond having to drop deep to mark Bojan, which allowed N'Zonzi and Whelan too much space. The introduction of Esteban Cambiasso at half-time helped address this imbalance and the Argentine also helped Leicester get more of the ball and move it quicker, if sometimes directly. Hamer overcame a nervous start to make a crucial late impact on his debut, and Wes Morgan and Liam Moore were excellent in central defence in front of him. Ulloa was isolated for large periods, but he held the ball up well and came up with the crucial goal - his third of the season. He could be the difference for the Foxes this term.
Sports Mole's man of the match
Glenn Whelan: Helped Stoke dominate the midfield in the first half with some strong tackling and driving runs forward, and tested Hamer with a couple of powerful shots from distance. He was unfortunate that the players ahead of him were not clinical enough to ensure that he was a winner today.
Biggest gaffe Stoke in general were guilty of being wasteful in a first half in which they did everything but score, and Crouch missed their clearest chance when he headed wide from eight yards out.
Michael Oliver is one of the Premier League's youngest officials, but he is arguably one of the best. He played a very good advantage to allow Leicester the break from which they scored the goal, and generally did not put a foot wrong all game. There was a feisty spell towards the end of the first half, but he ensured that things did not get out of control by producing yellow cards when he felt necessary, and stayed strong under some optimistic penalty calls. Spot on.
Stoke: The Potters travel to Queens Park Rangers in a week's time and are away from home again four days later when they take on Sunderland on the third round of the Capital One Cup.
Leicester: Their tough start continues when they welcome Manchester United to the King Power Stadium next weekend.