Runaway Championship leaders Leicester City saw their lead cut to nine points as Middlesbrough ended a four-game winless run with a stunning victory at the King Power Stadium.
Boro defended resolutely, surrendering possession and hitting the Foxes on the break to great effect as they took a 2-0 half-time lead through slick moves and tidy strikes from Finn Azaz and Sammy Silvera.
Leicester, who went close through Jannik Vestergaard and Patson Daka before falling behind, piled forward on the resumption.
And the introduction of Tom Canon at half-time, Kasey McAteer and former England striker Jamie Vardy with just under 30 minutes remaining, finally brought reward.