Ange Postecoglou branded Timo Werner's performance as "unacceptable" and not "anywhere near the level" required in Tottenham's Europa League draw with Rangers.
Werner was replaced at half-time of the Europa League tie at Ibrox by Dejan Kulusevski, who struck the equaliser with 15 minutes remaining.
Rangers deservedly led at the start of the second half through Hamza Igamane's strike, with Tottenham starting 18-year-old Archie Gray as a makeshift centre-back before bringing on another teenager in Lucas Bergvall with an hour played.
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Postecoglou's side are winless in their last five matches and the former Celtic boss was furious at Werner's display.
"He wasn't playing anywhere near the level he should," said Postecoglou. "When you've got 18-year-olds [playing], it's not acceptable to me and I said that to Timo. He's a senior German international.
"The moment we're in right now, it's not like we've got many options. I need everyone to at least be going out there trying to give the best of themselves. His performance in the first half wasn't acceptable."
Asked how Werner took the dressing down, Postecoglou added: "Don't really know. It's not really of great concern. We need everybody, including him, to be contributing because we don't have the depth to leave people out if they're performing poorly.
"We need them to play their part, especially the senior guys. When I'm asking younger guys to do massive jobs, I expect a level of performance from some of the senior guys and today wasn't that."
Werner joined Spurs on loan from RB Leipzig in January and then extended his stay until the end of this season. He has made 19 appearances this term and scored one goal.
Kulusevski: Everyone needs to do more
Tottenham goalscorer Dejan Kulusevski speaking to TNT Sports:
"Rangers played very well, we struggled a bit. We didn't play well enough to win the game. Rangers played a perfect game. It's a beautiful stadium, the fans helped them a lot.
"I wanted to change something, to make something happen and I succeeded once, but not enough today. It's always important to score but we've got to start winning games now. It's time to win on Sunday.
"Everybody needs to do a little more than we're doing now."
Boyd: Were Spurs trying?
Sky Sports' Kris Boyd:
"Philippe Clement will be the happier of the two managers. The financial gulf between the two teams is absolutely huge. That doesn't mean to say you can't go and get a result, and Rangers have shown that tonight.
"It took a terrific finish from Kulusevski when he came on to get Tottenham the equaliser, but Rangers throughout the game caused problems. They played really well, had some great individual performances. Nicolas Raskin was excellent in the middle of the pitch, Jefte and Ridvan Yilmaz.
"Tottenham, at some stages in that match, you just thought to yourself, 'are they actually trying? Are they working hard?' Because everything was so slow, even going to close Rangers' players down. They just looked off it.
"I get that they've got a lot of injuries, but that should give others an opportunity to show they're good enough to be at the club and forget about the ones that are injured.
"There are lots of top, talented players in that Tottenham team that are missing but I didn't think they'd done enough to win the game tonight."
(c) Sky Sports 2024: Timo Werner: Ange Postecoglou slams forward's 'unacceptable' performance in Tottenham's Europa League draw with Rangers