Ange Postecoglou lambasted an “unacceptable” second-half performance from Tottenham in their 3-2 loss at Brighton and admitted it was the worst defeat of his tenure at the club. Spurs were on course for a sixth consecutive victory in all competitions when Brennan Johnson and James Maddison struck before half-time to put them 2-0 up at Amex Stadium. That made it six goals in six matches for Johnson, but the Seagulls were transformed after the break with Yankuba Minteh able to reduce the deficit in the 48th minute. The impressive Georginio Rutter levelled 10 minutes later with a fine finish before ex-Arsenal forward Danny Welbeck completed the comeback when he headed home what proved the winner after 66 minutes. While Tottenham produced a dominant first-half display, they were second-best after and looked a shadow of the team which had entered this fixture after fine triumphs on the road at Manchester United and Ferencvaros. “That’s probably the most disappointing loss I’ve had since I’ve been here, in terms of the way we went about it and it’s something I need to assess,” Postecoglou reflected after his 51st match in charge of Spurs. “We didn’t do what you need to do at this level, it’s kind of non-negotiable. We just weren’t competitive."