Middlesbrough ended Brighton's club-record run of 22 league matches unbeaten with an impressive 3-0 victory at the Amex Stadium to move top of the Sky Bet Championship table.
Boro, who have now gone six league games without conceding a goal, led the penultimate Sky Sports 10 in 10 game after only five minutes through Kike, and Albert Adomah extended the visitors' advantage just before the break.
Leading scorer Cristhian Stuani sealed an emphatic win for the visitors midway through the second half in front of a crowd of 26,455 - including sacked Chelsea boss Jose Mourinho, a close friend of Boro boss Aitor Karanka.
Middlesbrough were bidding for an eighth win in their last 10 games and Mourinho, sporting a new haircut, had barely taken his seat when the visitors broke the deadlock in only the fifth minute.
Ghana international winger Adomah curled in a fine cross and Spanish striker Kike darted in front of German defender Uwe Huenemeier to head his first goal since August from 10 yards.
The Seagulls, who also started sluggishly in their previous home game when Charlton led by two goals after only five minutes, found it tough to get going.
Huenemeier, partnering skipper Gordon Greer in the centre of defence following Lewis Dunk's suspension, was sent flying by an aerial challenge from Boro skipper Grant Leadbitter, who was booked by referee Craig Pawson.
Albion striker James Wilson, on loan from Manchester United, threatened midway through the half when he eased past Daniel Ayala but drove over with his weaker right foot.
Midfielder Dale Stephens put a left-footed volley wide and Seagulls winger Rajiv van La Parra, on loan from Wolves, had a penalty appeal turned down after bursting into the box.
Running towards goal, Van La Parra hit the deck after a shoulder-to-shoulder challenge with defender George Friend but referee Pawson waved away the home side's appeal.
Boro doubled their lead with a minute remaining of the first half when Adomah struck with his fifth goal of the season.
A corner by Stewart Downing was headed on by Ayala and, after deflecting off defender Bruno, Adomah directed the ball home with his head from close range.
Brighton began the second half in more purposeful fashion and Boro goalkeeper Dimi Konstantopoulos came to his side's rescue 12 minutes after the break.
Good work by Israel international striker Tomer Hemed led to former Sheffield United winger Jamie Murphy having a goal-bound, right-footed shot skilfully tipped over by the Greek keeper.
Young defender Connor Goldson came on for his Brighton debut in place of the injured Huenemeier before Seagulls stopper David Stockdale saved smartly from Adam Clayton.
Boro, roared on by more than 2,000 travelling fans, effectively made the game safe in the 61st minute when Kike crossed accurately for Uruguay international striker Stuani to head home his ninth goal of the season from three yards.
Veteran Brighton striker Bobby Zamora came off the bench for the final 16 minutes and had an effort cleared off the line by Ayala after Van La Parra delivered a perfect cross.
Brighton boss Chris Hughton:
"Middlesbrough looked better than us. We've had two tough away games, had injuries as well and goals can change a game.
"We've now conceded four goals from corners in our last three games and that is something that needs to be eradicated. But we were up against a very good side and it's very difficult to be too harsh on the players."
Middlesbrough boss Airo Karanka:
"Jose brought us luck. We worked together at Real Madrid and it was an amazing experience. He is a friend of mine. I didn't tell the players that he would be watching but it wasn't a secret. Afterwards, he came into the dressing room to offer congratulations.
"It wasn't our best performance but we have beaten a team who were unbeaten."