Barnsley were beaten 4-1 at Championship leaders Fulham with new head coach Poya Asbaghi watching from the stands.
The Reds, under caretaker Jo Laumann, were 2-0 down at the break then conceded two more either side of a consolation goal by substitute Victor Adeboyejo.
After an even first quarter, the hosts totally dominated the match and could have won by several more goals before going to the top of the Championship with this win.
The Reds remain second bottom and four points off safety, with Asbaghi due to take over from Monday.
Laumann made six changes from the side that lost at home to Hull City before the international break.
Coming in were Toby Sibbick, Mads Andersen, Romal Palmer, Callum Styles, Dominik Frieser and Carlton Morris, who started after three months out with injury.
Jasper Moon and Aaron Leya Iseka dropped to the bench while Claudio Gomes and Devante Cole dropped out of the squad along with injured Liam Kitching and the suspended Callum Brittain. Obbi Oulare was on the bench.
Laumann also went away from the 3-4-3 formation favoured last season by Valerien Ismael and all this season by Markus Schopp then Laumann. They played a 4-2-3-1 with Sibbick at right-back and Jordan Williams on the left while Palmer was just behind Cauley Woodrow up front.
Barnsley had the first shot of the match in the tenth minute when Palmer's high effort from just outside the box was pushed over the bar by Marek Rodak after a good move down the left involving Morris, Williams and Woodrow.
Brad Collins then easily caught Michael Hector's 15-yard header from a left-wing corner by Harry Wilson. Collins was helpless minutes later as a shot by the same player from the edge of the box cannoned against the base of his right post after Tom Cairney's cross was headed by Tim Ream then touched by Neeskens Kebano.
The hosts took the lead after 25 minutes when Kenny Tete crossed from the right and Aleksandar Mitrovic beat Michal Helik in the air to head into the bottom left corner from seven yards out.
Barnsley were in the game until the opening goal but then it appeared like a training exercise until half-time with Fulham attacking almost constantly, particularly down their left where Sibbick was overwhelmed by Kebano, Robinson and Carvalho with little help from Frieser.
Styles almost scored a freak own goal when his pass went wide of Collins who rushed back to his goal line to gather.
The second goal arrived on 34 minutes when Fabio Carvalho cut in from the left wing, passed to Mitrovic whose attempted pass back deflected off Styles kindly into the path of Carvalho who blasted in from 15 yards.
It should have been 3-0 on 40 minutes when Antonee Robinson's cross from the left wing was missed by Williams and fell for Wilson on the right of the box eight yards out but he ballooned a shot well over.
Wilson missed another chance five minutes later when Harrison Reed's lofted pass over the visiting defence put him clean through after clever movement but Collins made a fine block with his chest.
The hosts began the second half as they ended the first. After a fantastic pass by Wilson, Carvalho crossed low for Tom Cairney whose 12-yard effort was deflected onto the crossbar. From the resulting corner, Mitrovic's header was kept out by a spectacular one-handed save by Collins diving to his left.
Barnsley reverted to 3-4-3, with Styles moving to left wing-back and Williams on the right. That seemed to stem the flow of Fulham chances and Barnsley almost pulled one back on 62 minutes when Woodrow's volley from outside the box was turned behind by Rodak.
It was 3-0 on 72 minutes when Wilson's cross from the right was met by Kebano who had got away from Williams and volleyed into the right of the net while sliding eight yards out.
It was almost 4-0 seconds later when another right-wing cross was headed by Mitrovic and it hit Sibbick's shoulder before being tipped over by Collins.
Barnsley pulled one back on 78 minutes, the first time Fulham had conceded in six games. Helik ended up on the left wing and behind the home defence then crossed for Woodrow who looked certain to score with a diving header but hit the post then substitute Victor Adeboyejo netted the rebound.
It was 4-1 three minutes later when Jean-Michael Seri, Fulham's £27million substitute, played a fantastic pass over the visiting defence to Wilson who chested down and beat Collins from close range.
Carvalho should have made it 5-1 in the 90th minute when Mitrovic was put clean through on the halfway line and ran into the box before squaring past Collins to the young attacker but he shot wide of an open goal under pressure from Styles.
Barnsley (4-3-3): Collins; Sibbick, Helik, Andersen, J Williams; Palmer (Moon 75mins), Benson, Styles; Frieser (Leya Iseka 55), Woodrow, Morris (Adeboyejo 75).
Unused: Walton, Oduor, Vita, Oulare.
Goals: Adeboyejo 78.
Fulham (4-2-3-1): Rodak; Tete, Hector, Ream, Robinson (Bryan 85mins); Cairney, Reed (Seri 80); Kebano (Onomah 80), Wilson, Carvalho; Mitrovic.
Unused: Gazzaniga, De Cordova Reid, Onomah, Mawson.
Goals: Mitrovic 25, Carvalho 34, Kebano 72, Wilson 81.