Mark Warburton has slammed Rangers’ "unacceptable" display against Hearts and admitted it could be the worst of his Ibrox reign.
The Gers boss was left dumbstruck as Ian Cathro's relentless Hearts side ran amok at Tynecastle in a devastating 4-1 win, which could have been worse had it not been for keeper Wes Foderingham's late heroics.
And Warburton admitted his team only had themselves to blame as another shambolic defensive display ensured they left Edinburgh empty-handed.
"We've just lost 4-1. We're Rangers Football Club, we don't lose 4-1. We did tonight and I feel frustrated, absolutely," he said.
"We weren't good enough second half. On Saturday against Motherwell, I thought it was as good as we've played in 18 months.
"Tonight, second half was as bad as we've played in 18 months if not the worst."
Poor defending allowed Krystian Nowak to head the hosts ahead after just four minutes before Emerson Hyndman volleyed Rangers level after 36 minutes.
However, the visitors fell apart after the break. Jamie Walker restored Hearts' lead after Andy Halliday's slip before grabbing another after Don Cowie had tapped home the third to ensure a second Tynecastle win over Rangers this season.
"To give away four minutes into the second half is just ludicrous. We win together and we lose together but that was way below the levels of Rangers Football Club," Warburton added.
"I didn't see it coming. Nobody did, the players or staff. We all have bad days at the office, like last time we were here, but we thought we had learned from the first visit not to give the crowd anything.
"But we gave away schoolboy errors at the start of each half. We have to be better than that. To give away those type of goals was unacceptable."
The travelling Gers support laid into their team at full-time and also took aim at Warburton when he replaced on-loan Bournemouth youngster Hyndman with 30 minutes remaining.
However, he said: "He is 20 years old, hasn't played many 90 minutes and on Saturday he played an outstanding 90 minutes. He is a young, precocious talent and Saturday took a lot out of him.
"The pitch out there is so heavy. We've got a responsibility to his parent club. We have got to look after their asset."
In contrast, Hearts coach Ian Cathro was delighted as his side eased a good deal of pressure on his shoulders with easily the best performance of his nascent regime.
He said: "I'm pleased that a lot of people have been able to let out some of the frustrations they've been through in the more difficult moments we've experienced so far.
"What impressed me most about the performance was that it lasted for 90 minutes. That's important.
"Isma Goncalves offers that tenacity, he attacks directly. He doesn't wait around, he goes and makes things happen. That's what we wanted in the squad. It was nice for him."