Swansea came from behind to rescue a point with a 2-2 draw at home to Wigan.
Home manager Graham Potter paid the price for a bizarre tactical switch in the first half as his team went to the break with it all to do following two Wigan goals from Joe Garner.
Potter rested captain Leroy Fer and Wales full-back Connor Roberts and plumped for an unusual 3-4-1-2 formation, but his side were abysmal in the first half.
Cian Harries, 21, started on the left of a three-man defence with Wayne Routledge and Dan James the wide options and Courtney-Baker Richardson and Oli McBurnie in attack.
Wigan were ahead in just the 10th minute. Cameron Carter-Vickers should have let the ball run to Swansea goalkeeper Erwin Mulder, but his poor clearance went straight to Kal Naismith. Inside the box, Naismith was bundled over by Routledge and Garner easily tucked home the resulting spot kick.
Only Van Der Hoorn's block stopped Sam Morsy from making it 2-0 to Wigan and Lee Evans then fired wide with Swansea all at sea.
James had a shot saved for the hosts, but Swansea looked clueless in attack and disorganised defensively as Evans was left in plenty of space to again go close with a header.
Wigan were dominant and it was no surprise when they doubled their lead. After a goalmouth scramble was cleared, Reece James whipped in a corner which Garner headed home.
Naismith should have made it three before the break, but Wigan turned around in control with a booking for Matt Grimes summing up Swansea's frustration.
Swansea were booed off and Potter changed things at half-time. Harries and Baker-Richardson were replaced by Jefferson Montero and Kyle Naughton as they reverted to a flat back four.
Routledge was now the attacking support to McBurnie as Wigan – who had been keen to waste time since the first whistle – saw James have a free-kick saved.
Swansea's change of system made a difference and they pulled one back when Grimes whipped in a corner. Van Der Hoorn rose, but the final touch came off Wigan captain Burn.
It was now a different game. McBurnie flicked wide and Wigan dropped deeper and deeper.
Potter threw on another striker, Wilfried Bony, in search of an equaliser and it arrived when Van der Hoorn converted a Bersant Celina corner.
Swansea pushed hard for a winner in four minutes of added time, but the game ended with a scuffle between Morsy and Van Der Hoorn who were both booked.