Boss Derek McInnes frustrated by McDiarmid Park pitch

St Johnstone defender Danny Grainger at Rangers' first goal
Grainger's error allowed Lafferty in to score for Rangers

St Johnstone boss Derek McInnes feels the state of their pitch must be taking its toll on team performances, after the 2-0 defeat by Rangers.

"We're not making excuses for tonight's defeat, it was a mistake by Danny Grainger which gave Rangers a goal," said McInnes.

"But it doesn't lend itself to fluency and can make you look foolish at times.

"I think it has affected our players a bit in home games as it's not easy to play on that."

St Johnstone matched Rangers for long spells of the meeting at McDiarmid Park, but went behind on 20 minutes, when Grainger's short passback allowed Kyle Lafferty to score.

Steven Naismith got Rangers' second late in the game to take the Glasgow side to the top of the Scottish Premier League.

Rangers boss Walter Smith also made reference to the poor condition of the pitch, but McInnes also admitted it helps and hinders his side in almost equal measure.

"Probably since the Celtic game when we lost 3-2 in October it hasn't recovered," he said.

"We've had nine clean sheets at home from 10 league games until tonight.

"The pitch is partly responsible for that as it's harder to create and score on it - we've found that in an attacking sense.

"We're not making excuses for the defeat tonight, it was a mistake by Danny which gave Rangers a lift without them having to do too much to get it.

"I thought the first 20 minutes of the game we were the better side and I don't think there was anything between the sides on a difficult surface."

The defeat put paid to any hopes St Johnstone had of finishing in the SPL top six, and their focus now is on their Scottish Cup semi-final against Motherwell.

"We've got to make sure we go into the semi in a good frame of mind - hopefully on the back of a couple of good results and performances," said McInnes.

"There's still a few boys who have semi-final places to play for; they've got to convince me they're ready to play."