Gregg Wylde admits Rangers will have to dramatically improve their performances if they are to avoid undoing their good start to the season.
His side, who have lost only once so far this season, remain top of the SPL after scraping past Inverness 2-1 at Ibrox - but it was a close run thing.
Kyle Lafferty scored a late winner after former Rangers midfielder Andrew Shinnie had cancelled out Carlos Bocanegra's opener.
But Rangers, who were booed off at half-time, were lucky not to concede a late winner as Caley hit the post and had a shot cleared off the line while a Richie Foran header which beat Allan McGregor was ruled offside.
"It was great to get the result but the performance wasn't good enough and we all know that," said Wylde.
"I'm not too sure (what's lacking), we will go to Murray Park training ground on Monday and speak about it and work on a few things.
"I know what the fans are saying. It was a bad day at the office basically, but the result was the important thing.
"The manager also said the performance wasn't good enough and we have to move on from it and hopefully we move on to it against St Mirren."
Caley manager and former Rangers captain Terry Butcher insists his side, one point off the bottom of the table, can take many positives from their performance
He said: "We are at the wrong end of the table but if we take our chances and defend a bit better we will be higher up but a lot of teams are saying that, it is ifs, buts and maybes. But to have gone away with nothing is hard to take, after putting a lot of effort in."