Steven Gerrard endured an unhappy 100th game in charge of Rangers, admitting his side were "unrecognisable" in their 2-1 defeat at Hearts.
Bottom of the Scottish Premiership table Hearts came back from a goal down to stun second-placed Rangers on Sunday - Liam Boyce scoring the decider in the 83rd minute after Steven Naismith had levelled up Ryan Kent's opener for Gerrard's team.
Having seen his milestone wrecked by Boyce's late winner, Gerrard said: "It was a poor performance. I didn't recognise us from the start of the game to the finish.
"Hearts deserved their win. They rushed us off the pitch and rattled us. They dominated us in terms of the ugly side of the game.
"We've been really organised, competed well and won second balls until now away from home, but there was nothing on either side of our game.
"It's always frustrating when you lose a game but I'm shocked as I didn't see that coming. You can lose a football match, but I didn't recognise my players and everything we work on daily."
The defeat was a bitter blow for Rangers' title hopes as they dropped five points behind Celtic, albeit with a game in hand.
Gerrard added: "We were really poor first half but we were at 0-0 and I could get into them at half-time.
"We got ourselves in front with a really good goal but then fell back into the trap seen during the first half. We've gifted them two goals. We had the best chances in the 90 minutes, four or five when we were through on goal, but we can't hide behind that.
"That's not the reason why we lost the game. We weren't good enough both in and out of possession, and more often than not that will mean you get beat."
Jambos manager Daniel Stendel was left smiling at the end as he finally claimed his first Ladbrokes Premiership victory at the seventh attempt.
Hearts' win and performance will fire belief that they can fight their way to survival as they clawed themselves to within a point of Hamilton.
"This is our castle and we need to make it difficult here," Stendel told Sky Sports. "It's a great day for us. We work hard on the pitch and training very hard and we have been trying to change things. The players believe in what we're trying to do and everyone fought today."
"We tried to play our game, and we came back. This is important for our mentality. I felt we deserved a point so I'm very happy with the win. It's a great day for us."
Barely 24 hours since completing his £150,000 move from Burton, Boyce enjoyed the dream debut, notching a goal and an assist.
"It was a brilliant debut for Liam," Stendel added. "He played well for us in the first half and I'm very happy for him that he scored the second goal to win us this game. He couldn't run with 30 minutes to go but he showed a good attitude for all of our players."