Chris Wood's derby double sent Nottingham Forest up to fifth in the Premier League after a dominant win at Leicester.
The striker seized on two second-half mistakes to punish his former club and take his league goal tally to seven this season.
Ryan Yates had given Forest a 16th-minute lead, only for Jamie Vardy to level soon after.
But the visitors recovered and Wood's clinical finishing ensured they have now lost just one of their opening nine games.
Foxes boss Steve Cooper suffered defeat against his old club - the first time he had faced them since being sacked last December - and watched on frustrated as Leicester were the architects of their own downfall, punished for every error they made.
First, Facundo Buonanotte opted to run out of defence with the ball rather than clear upfield and was robbed by Callum Hudson-Odoi on the edge of the area.
Elliot Anderson drove into the box and James Justin was only able to half clear his cross, which fell for Yates to find the bottom corner from 20 yards.
The lead lasted just seven minutes, though, as Harry Winks was slipped in on the left, and Vardy darted in between Murillo and Nikola Milenkovic to poke in the midfielder's cross from six yards.
Rather than settle Leicester down, the leveller galvanised Forest and Mads Hermansen brilliantly denied Nicolas Dominguez from point-blank range. The Danish goalkeeper also turned Hudson-Odoi's strike away before the break.
Forest then took complete control when they capitalised on more mistakes from the hosts. Wood made it 2-1 just two minutes into the second half when Leicester lost possession and he rolled Caleb Okoli to expertly find the corner with a low drive.
Hudson-Odoi then hit the post, but it still got worse for the Foxes on the hour when Wout Faes made a mess of dealing with visiting keeper Matz Sels' long clearance and Wood nodded over Hermansen.
Only a woeful Yates miss denied Forest a late fourth.