Sunderland suffered a second successive home defeat as Cardiff City earned a deserved win on Wearside. The Black Cats had picked up four points in their last two games on their travels at Luton Town and Huddersfield, but had lost their previous home game 4-2 against Burnley.
And Mark Harris' goal early in the second half was enough to inflict another defeat on home soil. Cardiff were the better side throughout and could - and should - have won by a much more convincing margin.
Anthony Patterson had made a brilliant penalty save from Joe Ralls in the first half, after Jaden Philogene had been fouled by Danny Batth. But Sunderland - despite the inclusion of Ellis Simms from the off - looked lightweight going forward, and they also gave the ball away far too cheaply in midfield which allowed the visitors to put them under pressure.
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Defeat saw Sunderland slip one place to 13th, and they are now level on points with the Bluebirds and above them only on goal difference. To make matters worse for Tony Mowbray, Luke O'Nien collected his fifth booking of the season meaning he will now miss next week's trip to Birmingham City through suspension.
Mowbray made four changes to the side that started the midweek win at Huddersfield, with Simms making his first start since returning from the toe injury he picked up in mid-September. Winger Jack Clarke returned from suspension, while midfielder Abdoullah Ba made his first start for the club and Dan Neil also returned to the side.
Leon Dajaku, Alex Pritchard, Elliot Embleton, and Corry Evans were the men to make way, with the latter trio included on the bench while Dajaku dropped out of the squad entirely. Cardiff caretaker-manager Mark Hudson made one change, in his case to the side that lost at home to Watford in midweek, with Sheyi Ojo replacing Andy Rinomhota.
In the opening five minutes, Clarke cut in from the left to fire a shot at goal which a defender headed out for a corner. But after that Sunderland surrendered the initiative to Cardiff, with the visitors looking increasingly threatening - not least because the Black Cats frequently gave the ball away cheaply.
Neil was left to breathe a huge sigh of relief when was caught in possession by Harris, and the Cardiff man played the ball to his right for Ojo but he fired wide from the edge of the box. Then on 13 minutes Sunderland conceded the penalty when Bailey Wright's overhit backpass had Patterson scrambling across the face of his goal, and Batth fouled Philogene to prevent him reaching the ball.
But Patterson came to his side's rescue, leaping to his left to beat away Ralls' spot-kick. Sunderland's best chance of the half came on the quarter-hour when Amad beat Ryan Allsop with a shot from inside the area on the right, but his effort was cleared off the line by Perry Ng.
Patterson made a save from the tricky Philogene, and there was another lucky escape for the Black Cats when Niels Nkounkou slid the ball into the left-hand channel for Harris but while he steered his shot wide of the oncoming keeper, he also sent it wide of the post. Sunderland needed to up their game in the second half, but the improvement did not come and they fell behind within five minutes of the restart.
Mahlon Romeo was afforded far too much room down the right to advance on the penalty area, and he tried a low shot which was going wide until Harris diverted it in. Sunderland appealed for an offside decision against Harris, but the linesman's flag stayed down.
With a lead to protect, Cardiff made sure they did not commit too many men forward and that made it difficult for Sunderland to break them down. They carved out a chance 20 minutes from time when Luke O'Nien won the ball on the right and his deflected cross found Simms at the near post, but his header landed on the roof of the net.
Cardiff sub Max Watters saw a shot saved by Patterson before Sunderland immediately went upfield and sub Embleton saw an effort saved by Allsop as the game became end-to-end in the final ten minutes. But ultimately Sunderland failed to find an equaliser, and in truth they did not deserve one.
How they lined up
Sunderland: Patterson, O'Nien, Wright, Batth, Cirkin, Neil (Pritchard 57), Ba (Evans 57), Roberts (Bennette 67), Amad, Clarke, Simms (Embleton 73). Subs not used: Bass, Matete, Hume
Booked: Batth, Neil, O'Nien, Embleton
Cardiff City: Allsop, Romeo, Ng, Kipre, Nkounkou, Wintle, Ralls, O'Dowda (Rinomhota 73), Philogene (Sawyers 58), Ojo (Nelson 73), Harris (Watters 58 (Whyte 90+3)). Subs not used: Alnwick, Sang
Booked: Wintle, Nkounkou, Kipre
Referee: Andy Davies (Hampshire)
Attendance: 37,015