The home side should have taken an early lead in the Scottish Premiership clash after some sloppy Aberdeen defending, but Christopher Kane was denied at close range by the on-rushing Scott Brown.
Aberdeen had a golden opportunity of their own to go ahead after a sloppy back-pass from David Wotherspoon, but Alan Mannus sprinted off his line to deny Peter Pawlett.
On the half-hour mark St Johnstone took advantage of their first-half dominance. A cross into the box was headed up in the air by Andrew Considine and Simon Lappin was on hand to smash home a volley when the ball dropped.
St Johnstone almost doubled their lead but Brown got down to save Wotherspoon’s long-range shot and Kane’s follow-up effort.
Aberdeen should have gone into half-time level after a goalmouth scramble but Niall McGinn was unable to turn the ball home. From the subsequent corner, David Goodwillie headed on to the crossbar as St Johnstone went into the break with a narrow advantage.
High-flying Aberdeen scored a sensational equaliser on 57 minutes with their first clear-cut opportunity of the second half. Goodwillie nodded into the path of Rooney who took a touch before lashing the bouncing ball into the top-right corner despite an outstretched hand from Mannus.
But Saints should have reinstated their lead on the hour mark after Lee Croft delivered a perfectly-weighted cross for Kane, who fluffed his lines with the goal at his mercy.
The Dons almost went in front in spectacular fashion through Goodwillie’s acrobatic overhead kick which landed on the roof of the net.
On 82 minutes, Shay Logan delivered a pinpoint cross for substitute Cameron Smith who was unable to guide his header on target.
Moments later Rooney almost notched his second of the game with a low drive that Mannus managed to scramble clear.
St Johnstone almost snatched victory with two gilt-edged opportunities in added time but neither Murray Davidson nor Steven MacLean were able to beat Brown as honours at McDiarmid Park ended even.