The fairytale continues in Europe as Leicester became the first Champions League debutants to win their group since Malaga in 2012.
Leicester are toiling in defence of their 5,000-1 Premier League title, but the fairytale continues in Europe as they became the first Champions League debutants to win their group since Malaga in 2012.
Porto's failure to beat FC Copenhagen left Leicester five points clear at the Group G summit, guaranteeing them a kinder draw for the last 16 even before their final match away to Porto on December 7.
"We're on another journey. I don't know where, but we're excited!" said Leicester manager Claudio Ranieri.
"We started well, we pressed, scored twice and kept possession. But after they scored we lost our way a little.
"Now the group is won, it's important to come back in the Premier League."
The only disappointment for Ranieri's side, who sit two points above the relegation zone in the Premier League, was a second-half goal by Brugge's Colombian winger Jose Izquierdo.
It prevented Leicester from becoming the first team since Manchester United in 2010 to keep clean sheets in their first five group games, but that was of secondary importance on a historic night.
Brugge's defeat at the King Power Stadium was their fifth in succession in the group and extinguished the Belgian champions' faint hopes of pipping Copenhagen to a Europa League place.
Leicester had needed less than five minutes to get off the mark in their 3-0 win in September's reverse fixture and they were just as quick to get going in the teams' reunion.
A sharp break down the left wing involving Marc Albrighton and Jamie Vardy culminated in Christian Fuchs curling a delightful cross behind the visitors' defence that Okazaki hooked home at the near post.
Leicester's Jekyll and Hyde transformation had taken place once again and they swarmed all over their punch-drunk opponents in a manner reminiscent of last season's extraordinary title surge.
Mahrez turned Laurens De Bock inside-out before drawing a near-post block from Brugge goalkeeper Ludovic Butelle, who also gathered a shot from Okazaki after Vardy nixed Brandon Mechele's attempted clearance.
In the 29th minute it was 2-0, Mahrez sending Butelle the wrong way from the penalty spot after Albrighton had lured Dion Cools into an untidy challenge on the edge of the box.
It was the Algeria winger's fourth goal of the campaign, strengthening his position as the top scorer in the group.
Leicester goalkeeper Ron-Robert Zieler, deputising for Kasper Schmeichel, could not have wished for a gentler start to his competition debut, although he did have to box away a curler from Izquierdo.
Leicester went into half-time as the last team in the competition still to concede a goal, but that statistic would change within seven minutes of kick-off in the second half.
After winning the ball back in his own half, Izquierdo set off on a charging run down Brugge's right flank before thumping a shot high past Zieler at his near post.
Players on both sides had goals chalked off for offside -- Vardy for Leicester, Claudemir for Brugge -- before the hosts were given a scare when substitute Anthony Limbombe sliced wide.
Seeking to keep Brugge on the back foot, Ranieri sent on the fleet-footed Jeff Schlupp and Demarai Gray for goal-scorers Mahrez and Okazaki, with Ahmed Musa following shortly after.
Schlupp almost made an immediate impact, seizing on a loose pass and dispatching a low shot that Butelle dropped to his left to save.
Ricardo van Rhijn's corners gave the hosts some nervy moments late on and Butelle twice prevented Gray from making it 3-1, but Leicester would not be denied their place among the continental elite.
"In football at this level, you have to play 90 minutes," said Brugge coach Michel Preud'homme.
"The first half was a disaster and the second half was our best level."