The build-up was dominated by the bold – and perhaps belated – decision to leave out-of-sorts captain Wayne Rooney on the bench, but it was another jilted player that rose to the fore in Ljubljana.
Hart, unfancied by Manchester City boss Pep Guardiola and shipped out on loan to Torino, produced a string of crucial saves to frustrate Slovenia and secure England a 0-0 draw in a tough World Cup qualifier.
Just 10 minutes were on the clock when Eric Dier, picked ahead of Rooney, twice gifted the hosts possession in a matter of seconds, with his goalkeeper denying Roman Bezjak before Jasmin Kurtic hit the post.
England failed to muster a shot on target in the first half and that stuttering display continued after the break, with Hart producing a stunning save to push a Kurtic header onto the crossbar and then away.
The 66-cap goalkeeper was again required to frustrate the impressive Josip Ilicic and interim manager Southgate turned to Rooney with 17 minutes left.
The substitute came close from the edge of the box soon after his introduction but there was to be no Hollywood ending, with the Three Lions having to settle for a fortuitous point.
This was England’s second trip to Ljubljana in the space of 16 months, but their 100 per cent record in this fixture looked unlikely to continue from the outset.
Lax passing and poor decision-making showed how much the intensity was effecting the visitors, with that discomfort epitomised by Dier casually passing back to Hart and inexplicably failing to see Bezjak.
The Torino goalkeeper rushed off his line to thwart the striker, but when the ball came back into the box Dier’s rushed clearance went straight to Kurtic, whose fine, curling effort hit the far post.
It was a let-off 10 minutes into a match that Daniel Sturridge had already managed three chances, yet his biggest threat was from a turn soon after. His drive into the box was ended by the shoulder of Rene Krhin, but no penalty was awarded much to his and Southgate’s evident chagrin.
Dier and Sturridge were similarly frustrated when handed bookings for late challenges as England tried to force an opener, rather than create one.
Few were showing willing or attacking nous, with a speculative Theo Walcott drive over and deflected John Stones strike the best they could muster before half-time.
The former Barnsley centre-back was displaying composure and confidence lacking in many team-mates, with a rare passing move late in the half ended by Kyle Walker’s poor cross – one that saw the right-back throw up the turf in disgust.
The pitch was poor but Slovenia were having no such problems and threatened to break the deadlock within 30 seconds of the restart.
Exceptional poise and skill from Ilicic, along with a fine one-two, saw the Fiorentina attacking midfielder through, only for his cutback to evade his team-mates.
Hart was called into action to prevent Bostjan Cesar bundling home from a corner soon after, before the Three Lions goalkeeper remarkably denied the home side.
Kurtic’s flicked header was bound for the top corner until Hart’s inspired intervention, pushing the ball onto the crossbar and somehow flicking it away on his way down. England fans made their appreciation known as Hart received treatment as he fell awkwardly, before Ilicic robbed Stones and struck just wide.
Jan Oblak comfortably dealt with a Dele Alli effort just before that – the visitors’ first effort on target – with substitute Andros Townsend brightening up the attack with a snapshot.
But Hart was soon back in the action again, smothering Ilicic after he skipped past Gary Cahill following a Henderson pass.
With 73 minutes on the clock, and Slovenia forced into a defensive reshuffle following an injury to captain Cesar, Southgate brought Rooney on for the ineffective Alli.
It was a decision that nearly paid immediate dividends, with the captain hitting just wide from the edge of the box.
Danny Rose cut inside and snatched at his shot as England attempted to snatch a winner, with Sturridge trying his luck and Jesse Lingard forcing Oblak into action.
Tempers became frayed as the match entered the final minutes.
Slovenia felt a bad Cahill challenge should have brought more than a booking, with Lingard given a yellow card after reacting angrily to Aljaz Struna, who was also put into referee Deniz Aytekin’s notebook.
Slovenia: Oblak, Struna, Samardzic, Cesar (Mevlja 68), Jokic, Kurtic, Krhin (Omladic 84), Birsa (Kronaveter 59), Verbic, Ilicic, Bezjak. Unused substitutes: Belec, Skubic, Jovic, Crnic, Novakovic, Trajkovski, Zajc, Pihler, Koprivec.
England: Hart, Walker, Cahill, Stones, Rose, Henderson, Dier, Alli (Rooney 73), Walcott (Townsend 62), Sturridge (Rashford 81), Lingard. Unused substitutes: Forster, Smalling, Gibbs, Antonio, Keane, Oxlade-Chamberlain, Vardy, Pickford.
Referee: D Aytekin (Germany).