St Johnstone manager Steve Lomas has accused Rangers of acting like "a little club" over their pursuit of Francisco Sandaza.
Rangers have submitted a pre-contract offer for the striker, who is out of contract at the end of the season.
But Lomas, who saw his side lose 2-1 to the champions, hit out at the conduct of Rangers and owner Craig Whyte.
"I do believe there should be a bit more leadership from the top at Rangers," he said.
"Ally McCoist has got a difficult job because of the finances and he has had to follow Walter Smith, who is a legend, so he has a tough job.
"But this wouldn't happen if David Murray was at the club; he wouldn't let it.
"Rangers are a big club but unfortunately they are behaving like a little one."
Prior to kick-off, Lomas told BBC Scotland that Rangers had offered Sandaza a two-year contract to move to Ibrox in the summer.
And he is frustrated that Rangers have chosen this approach rather than offering a fee to take Saints' leading scorer now.
"We haven't even had an offer," Lomas added.
"As a boy, I was a Rangers fan. They are great fans, the Rangers fans, and I'm sure they must be feeling slightly miffed that they can't go out and pay for Fran Sandaza.
"I would be worried, especially a guy who is in the last months of his contract. I would be extremely worried if I was a Rangers fan."
Lomas is also unhappy with Sandaza's agent, Clive Jagger.
He said: "As for his agent, we still haven't heard if he's turned our offer down - probably as big an offer as St Johnstone have ever made in their history, which I think is slightly disrespectful to us.
"He's on the TV saying this and that. No doubt he wants him to go to Rangers because he will be getting something."
A double from Nikica Jelavic secured the points for Rangers, either side of an own-goal from Carlos Bocanegra.
But Saints were furious with the positioning of a free kick that led to Rangers' opener.
Lomas said: "Unfortunately we are talking about a refereeing decision again.
"I like Craig Thomson, I think he's a fantastic referee and it's by no means a witch hunt from me, but I said to Craig he got it wrong after the game.
"Whenever there is an offence the foul has got to be taken where it's committed, not seven yards away. I'm all for football being played quickly but it's got to be at the right position. It's a bitter one to take."