Wes Morgan's first goal of the season earned Leicester City a 1-0 victory over Southampton to move them seven points clear at the top of the Premier League.
The Foxes captain rose highest on 38 minutes to head Christian Fuchs' cross home to seal a hard-fought victory which moved them to within four wins of a maiden top-flight crown.
Until that point it appeared the nerves may be getting the better of Claudio Ranieri's side as the Saints pushed for the breakthrough, with Sadio Mane controversially denied by Danny Simpson's arm in the first half.
But Leicester produced a resolute defensive display and arguably could have enjoyed a more comfortable afternoon had it not been for the heroics of Saints goalkeeper Fraser Forster.
The result sees Leicester move seven clear of second-placed Tottenham and 11 clear of Arsenal, while Southampton remain seventh on 47 points.
For the fourth game running Ranieri opted for his tried and tested starting line-up and named an unchanged side while Southampton made four changes, with Cedric Soares, Matt Targett, Victor Wanyama and Mane drafted in to start.
And the hosts' continuity saw them make the more positive start, with Riyad Mahrez and Jamie Vardy both supplying driven crosses from either flank which Shinji Okazaki failed to connect with inside 20 minutes.
Those two chances in quick succession kicked Southampton into life, as Graziano Pelle headed the visitors' first clear chance onto the roof of the net shortly before the half-hour mark.
Mane was then denied the opener three minutes later when, having rounded the on-rushing Kasper Schmeichel, he saw his goal-bound effort strike Simpson, with replays confirming contact with the Leicester full-back's arm.
The incident went unpunished but Southampton carried on undeterred as Fonte's long-range strike forced Schmeichel into a fine save, before Jordy Clasie whistled a shot wide.
Having survived the Southampton onslaught Leicester hit back to devastating effect, as Fuchs crossed for his defensive partner Morgan to tower over Clasie to head the league leaders in front.
It proved to be a lead they would not surrender as Southampton threatened to haul themselves back into the game but always looked susceptible on the counter.
Fonte almost doubled Leicester's advantage for them, inadvertently sending Drinkwater's cross looping over Forster, only for the England stopper to claw the ball from under his crossbar with a brilliant save on 61 minutes.
Forster was called upon again to thwart Simpson from close range, after great build up play from Vardy and Drinkwater 10 minutes later, although the full-back should have scored.
The Saints were denied a penalty on 73 minutes when substitute Charlie Austin saw his cross strike Robert Huth's arm, but referee Michael Oliver was unmoved.
Five minutes from time, Vardy's low shot was kept out by Forster as he completed a hat-trick of exceptional saves.
However there was little else Forster could do to take the gloss off an afternoon which saw Leicester's unlikely title bid gather yet more pace thanks to their fifth 1-0 win in six matches.
Super Sunday verdict - Graeme Souness
Leicester were nervy today. They didn't play any football today. They defended like demons - and for as much of the ball as Southampton had, they didn't make the goalkeeper work.
You have to say they are resilient and if the punch on the nose comes in the next six games, history this season tells you they'll bounce back.
Leicester: Schmeichel (6), Simpson (7), Morgan (8), Huth (8), Fuchs (8), Mahrez (6), Drinkwater (8), Kante (7), Albrighton (7), Vardy (8), Okazaki (6).
Used subs: Gray (6), Ulloa (6), Dyer (6).
Southampton: Forster (8), Cedric (6), van Dijk (7), Fonte (7), Bertrand (7), Wanyama (6), Clasie (6), Davis (7), Mane (7), Targett (5), Pelle (6).
Used subs: Tadic (5), Ward-Prowse (5), Austin (5).
Man of the Match: Wes Morgan