Kevin Mirallas and Romelu Lukaku struck to sink Leicester 2-0 and hand Everton their first away win since September.
The pair scored breakaway second-half goals to send the Toffees seventh in the Premier League following a 2-0 victory at the King Power Stadium, which increases the champions’ relegation worries.
It was only Everton’s third triumph from their last 13 Premier League games but Ronald Koeman’s side ground out all three points in a low-quality game.
The last time Leicester hosted the Toffees, in May, they lifted the Premier League trophy afterwards, but this time they are three points above the relegation zone.
That the bottom three continue to struggle is a saving grace but boss Claudio Ranieri needs his side to rediscover their spark during a period which he has already said will define their season.
Leicester have won just two of their last 13 games in all competitions and, without the banned Jamie Vardy, rarely looked like scoring.
Around 30,000 Vardy masks were left on seats for supporters before the game, a move widely thought to be a response to the striker’s three-match ban.
The Foxes failed to get his suspension overturned, following a red card at Stoke last week, despite an appeal to the Football Association with boss Claudio Ranieri and owner Vichai Srivaddhanaprabha both speaking out against the dismissal.
FA chairman Greg Clarke attended the game and was photographed pretending to wear a mask but regardless of their feelings, the Foxes must do without Vardy for another two games.
They missed his presence and replacement Shinji Okazaki was withdrawn at half-time while Riyad Mahrez, last season’s PFA Player of the Year, was dropped for Demarai Gray.
Former Birmingham winger Gray was a rare bright spot for the Foxes during a dire first half as he helped them dictate the early play as he and Daniel Amartey tried their luck from distance.
Everton held firm but lacked any intensity to threaten the hosts with Lukaku isolated, although the striker’s minimal movement did little to help his, and his team’s, cause.
The Foxes formed a blue wall any time Everton pressed, with Islam Slimani often the only man in front of play, but the visitors were far too pedestrian.
With no focal point, and Lukaku quiet, the Toffees had to wait until three minutes before the break to have their first effort and even then it was a token header over by Ramiro Funes Mori.
Leicester’s tempo had subsided and Danny Drinkwater replaced Okazaki at half-time but, within seven minutes, the hosts were behind.
Without the banned Robert Huth the Foxes hesitated when Joel Robles launched a huge clearance from his own area, which dropped between Wes Morgan and Marcin Wasilewski, Huth’s replacement.
Mirallas split the defenders with his run and, as Morgan slipped, the forward’s shot clipped Wasilewski which took it over Kasper Schmeichel’s trailing leg and into the corner.
The goal reinvigorated Everton with the hosts increasingly frustrated and the home supporters jeered Ranieri’s decision to replace Gray with Leonardo Ulloa in the 66th minute.
But the call almost paid off instantly when Ulloa headed straight at Robles – although the striker should have scored.
Mahrez also replaced Andy King as Leicester searched for a response and the Foxes went long to Ulloa and the previously anonymous Slimani in their attempts to recover.
But Ashley Williams and Funes Mori handled any pressure and Idrissa Gana should have made the game safe with seven minutes left.
With Leicester pushing forward gaps appeared at the back and Lukaku exploited the space down the right to cross for the unmarked Gana who, on the stretch, directed the ball over from six yards.
Everton did eventually finish off Leicester in injury time, though, when Lukaku latched onto Ross Barkley’s clearance, held off Morgan’s challenge, cut inside and slipped the ball under the advancing Schmeichel.