The Robins trailed 22-4 at half-time after an abject first half at the KC Lightstream Stadium and, although they fought back to level the scores knowing a draw would have been enough to secure their place in Super League, they were denied by a late Danny Brough drop goal.
Webster said. “How you think you can win a game doing that when the other team completes at 90 percent is madness, absolute madness.
“We spoke in the week about not pushing any passes but that’s what we did. We put ourselves in a really poor position.
“I’m really proud that we came back from it but we gave ourselves too much to do.”
While Huddersfield can now plan for 2017, Rovers must prepare for a sudden-death showdown with either Salford or London Broncos at the KC Lightstream Stadium next Saturday.
“We need to pick ourselves up and prepare well for Salford or London,” said Webster, who will remain in charge for one last match before handing over the reins to Tim Sheens, the current director of rugby at Salford.
“It’s big game, there’s no hiding from that.”
If Salford beat Batley on Sunday to clinch their spot, Sheens will step aside for Saturday’s game to avoid a conflict of interests.
However, it could have been so different had the game taken a different twist in an epic finish.
Hull KR skipper Terry Campese almost snatched a draw with a 40-metre drop goal that bounced back off an upright while centre Thomas Minns had a try two minutes from the end disallowed for an obstruction in the build-up.
Webster had no complaints over the disallowed try but cast doubt over the validity of Brough’s drop goal.
“I thought there was a push in the build-up,” he said. “I’m not sure the drop goal went over. It looked to be like it went over the top of the sticks. It’s a game of inches sometimes isn’t it?”
Hull KR head of rugby Jamie Peacock, who was playing in the third match of his comeback, had no doubt that Brough’s goal should have been ruled out.
“Beaten by a drop goal that missed,” Peacock said on his Twitter account. “Outstanding support - it was a cauldron. Be there one more time for us.”
Huddersfield coach Rick Stone, who joined the club in July on a contract that runs to the end of 2018, was relieved to get the win.
“It wasn’t pretty in the second half and our management could have been better but we showed plenty of tenacity when we needed it,” he said.
“It was a tough ask to come here and win. We got away to a decent lead and with the breeze they fought back.
“It wasn’t textbook at the end but the result was the only thing that mattered.
“It’s been an interesting couple of weeks but I’ve really enjoyed it.
“We can start planning a bit now, which is nice, We haven’t had the luxury of being able to do that up until now. Just now, we’re going to enjoy the moment.”
Amid the late drama, Ryan Brierley’s first-half heroics for Huddersfield were almost forgotten as he took his try tally to eight in just four appearances in the Super 8s and also created one for Leroy Cudjoe to put his side in total command.
“He added some touches of class,” Stone said. “He’s still learning but he’s a tryscorer and that’s what the game needs. He’ll get better and develop as we go along.”