Rangers' first-half display in their 2-1 Scottish Premiership victory over St Johnstone left manager Steven Gerrard "really worried".
However, the Ibrox boss praised his side's "character" as two second-half goals by Alfredo Morelos lifted them into second place in the division.
Matty Kennedy had given St Johnstone the lead before Rangers recovered to move within a point of Celtic.
"That's not a Rangers team or showing in that first half," Gerrard said.
In his interview with RangersTV, he added: "You've seen the two sides of us. I'm really worried about the first-half showing but delighted at the second."
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St Johnstone were unbeaten in eight of their previous nine matches, winning six, and scored just before the break at McDiarmid Park to seize control.
Rangers' players were jeered by their own support at half-time, and Gerrard said he made an "honest" assessment of their performance in the dressing room.
Speaking on BT Sport, he added his side "shouldn't have to work that hard to win at places like this".
"They were quite within their rights to boo even louder because that wasn't acceptable," he added on RangersTV.
"We didn't have an individual doing the shirt justice. But they deserve credit for the second-half performance. I thought we played with purpose, we showed bravery, personality and character.
"We played like a team that really fancies getting involved at the top end of the table."
Gerrard revealed Croatian left-back Borna Barisic, who had to be replaced early in the second half after what looked like a hamstring injury, will be sidelined until the new year.