Islam Slimani scored either side of half-time and Ben Mee put in to his own net as Premier League champions Leicester City secured victory over the Clarets at the King Power Stadium.
Boss Sean Dyche transformed his system for the first time since December in a bid to contain the Foxes, moving to a 4-5-1 formation that catered for record signing Jeff Hendrick's first start for the club.
And the new look line-up, which saw Johann Berg Gudmundsson and Sam Vokes miss out, proved effective until the closing seconds of the first half.
Claudio Ranieri's side, who beat Club Brugge in their opening Champions League group fixture midweek, barely had a sniff as the visitors worked tirelessly to keep their opponents at bay.
Daniel Amartey missed the target by some distance when firing on the turn after Marc Albrighton's corner had dropped for him inside the penalty area.
The spectacularly skilfull Riyad Mahrez was, as expected, tricky and troublesome as the hosts attacked the flanks in a bid to avoid a congested central midfield battle area.
And the 25-year-old appeared to be the key that was the most likely to unlock the Clarets defence. The Algerian skipped past Stephen Ward midway through the half, forced Mee on to the back foot but saw his low effort saved by the legs of Tom Heaton.
The two recent Championship title winners then had opportunities to take the lead within minutes of each other.
The first chance fell to Stephen Defour, who opened his Clarets account with a stunning strike in the 1-1 draw with Hull City last weekend.
The Belgian international was unmarked and well positioned when Scott Arfield headed George Boyd's delivery back across goal but the former RSC Anderlecht man guided his effort straight at Ron-Robert Zieler.
At the other end, nobody was able to track the run of Mahrez as the one-time Le Havre winger peeled goal side of the visiting defence but he steered Christian Fuch's cross wide of the near post.
Once Heaton plunged to his right hand side to claim Slimani's strike from the edge of the box it seemed the Clarets would see the half out.
However, the Foxes capitalised on a calamitous moment to take the lead in stoppage time. Matt Lowton was the prosecuted party, with referee Anthony Taylor penalising the full back for crashing in to Albrighton who wasn't posing a threat with his back to goal.
Fuchs swung in the resulting set-piece and Slimani, on his debut in the top flight having joined from Sporting Lisbon for £29m on deadline day, stole a yard from Ben Mee to power a header past Heaton from close range.
It was a huge blow for the Clarets but that pain and disappointment was exacerbated in the embryonic stages of the second half.
Mahrez provided the threat as he broke in to the penalty area, Jamie Vardy supplied the flick from the subsequent centre and Slimani obliged with a header from inside the six-yard box to make it 2-0.
The home side bossed possession in the second period, with the Clarets struggling to have an impact on proceedings, and both Mahrez and Fuchs went close to extending the advantage.
Mahrez's attempt travelled just over the bar after taking a deflection on its way through while the Austrian defender's shot was diverted wide of the near post.
The English champions did get on the scoresheet again, though, with a little help from the Clarets.
Mahrez was unsurprisingly in the thick of the action as he played the ball in to the box and Mee inadvertently poked the ball in to his own net after sticking a toe out in an attempt to block.
The Clarets showed up in the final third in the latter stages but they failed to inject a genuine goalscoring threat.
Zieler, on his bow, adjusted his feet well to beat substitute Johann Berg Gudmundsson's deflected free-kick to safety before Vokes, on for Defour, glanced a header wide of the upright from Ward's cross.