ABERDEEN FC boss Mark McGhee will have his defence on red alert tonight against a free-scoring St Johnstone attack.

Saints are the highest SPL scorers outside the Old Firm this season, and have leap-frogged Aberdeen FC into seventh place in the league.

The promoted Perth club hammered Hibs 5-1 and McGhee is well aware of the potential threat that could kill the Dons’ top six hopes.

He said: “Beating Hibs 5-1 was an extra-ordinary result. We have to go into tonight’s game considering that score because St. Johnstone have proved they are capable of performances like that.

“They have a big powerful striker in Kenny Deuchar who is very effective.

“Deuchar gives the defenders a tough time and is also a proven goal-scorer.

“They have goals in the team so we must be solid at the back and be able to create chances ourselves.

“St Johnstone will also be thinking about catching Hearts, and to do that will also feel they have to beat us tonight.

“St Johnstone have a lot to play for in this game as well so we are expecting a tough test.”

Aberdeen trail sixth-placed Hearts by seven points but crucially have two games in hand.

Tonight’s game in Perth is the first of those matches and McGhee wants a much improved performance from his squad.

“My players must be up for the challenge and prove that they can push for the top six,” he said.

“To do that they must step up a gear and battle.”