St Johnstone gave their survival chances little hope, leaving Easter Road without having put up any semblance of a fight.
With far too much room to manoeuvre Junior Hoilett fired a brilliant curling shot into the top corner in the 18th minute.
Failing to heed the warning of the first, St Johnstone were soon two down before the half-hour mark courtesy of a cute finish from talisman Martin Boyle.
Kieron Bowie continued to impress since returning from a long term injury, winning Hibs a penalty in the dying minutes of the game. Calmly slotting his penalty home to see Hibs slip away, sealing the already secured three points.
Despite finding themselves five points adrift at the bottom of the table, St Johnstone played in a far more relaxed fashion than their status suggested.
Under little pressure at the back but struggling to create any opportunities of note as Hibernian harangued them on the break, there was little for Jordan Smith to do on the day.
A first half that could have been far worse for Simo Valakari had Mykola Kuharevich not missed a gilt-edged chance with the goal at his mercy following Boyle’s low cross.
Beyond a powerful shot from Kieron Bowie, well saved by Andy Fisher, there was little of note to speak of until the eventual penalty, the visitors unable to put together a dangerous attack despite the flurry of changes from the manager at the interval.
Victory means Hibs have suffered just one defeat from the last eighteen in all competitions.
St Johnstone meanwhile could find themselves eight points off the relegation play-off places should Dundee pull off an unlikely victory at home to Rangers.
Line-ups:
Hibernian: Smith, Iredale, Bushiri, Miller, Obita, Levitt (Manneh 74), Triantis, Cadden, Hoilett (Campbell 88), Kuharevich (Bowie 65), Boyle (c) (Gayle 74) Unused subs: Bursik, Molotnikov, Ekpiteta, Moriah-Welsh, O’Hora
Booked: Iredale
Goals: Hoilett (18), Boyle (29), Bowie (90+5)
St Johnstone: Fisher, Douglas (Carey 59), Mitchell, Balodis, Wright (Steven 46), Holt, Sprangler (c), Curtis (Duke-McKenna 46), Svedberg (Clark 82), Griffith, Kirk (Kimpioka 46) Unused subs: Sidibeh, Sinclair, Smith, Steven, Watt
Booked: Sprangler, Svedberg, Holt
Goals:
Referee: Mathew MacDermid