But with eleven minutes left substitute Kyle Lafferty drilled home a superb free-kick to set-up a grandstand finish.
With the regulation 90 minutes almost up Kevin Kyle was guilty of missing a simple header before Kello made a superb point blank save from Lafferty and Davis hit the post.
When the fourth official announced their was five minutes of injury time to play the Light Blues saw their chance and on 93 minutes Steven Naismith linked up with Lafferty before toe poking the ball past the helpless Hearts keeper in front of the travelling Bears.
It was truly memorable comeback from the visitors who again had to dig deep in to their energy reserves to pick up all three points from this stunning SPL clash.
Lee McCulloch and Kirk Broadfoot missed this afternoon’s action following the midweek victory over Bursaspor with Nikica Jelavic and Vladimir Weiss taking their places.
McCulloch was suffering from a hip injury while Broadfoot was a doubt ahead of the match after collecting a knock to his foot.
And as expected Smith reverted to a 4-4-2 on the return to SPL business as the Light Blues looked for a seventh straight win at the start of the campaign.
With Broadfoot dropping out the back four had a familiar look to it with Steven Whittaker and Sasa Papac on the flanks and Davie Weir partnering Madjid Bougherra in the middle.
Mo Edu filled McCulloch’s role in the centre of the park alongside Davis, with Weiss taking the left flank and Naismith on the right.
As with any match played at Tynecastle the atmosphere at kick-off was electric and Rangers showing no signs of tiredness.
Hearts also showed a desire to push forward early on with Kyle and Calum Elliot playing up top as part of a 5-3-2 formation used by Jim Jefferies.
It was the Light Blues, however, that had the first real chance of the game when Edu found a gap to exploit but his left-foot shot was blocked.
On eight minutes Davis then burst forward and having found Jelavic in space on the right his shot across goal was parried by Kello.
The ball landed back the feet of the midfielder but with the keeper grounded the Northern Ireland star’s net bound effort was cleared off the goal line.
The early misses proved costly as Skacel opened the scoring against the run of play.
It was Kyle that flicked a long ball in to the path of the Czech who evaded two challenges from Weir and Bougherra before firing the ball in to the empty net with McGregor grounded.
Rangers immediately looked to respond and when Naismith was brought down on the right by Obua a Davis free-kick was met by Papac but the Bosnian’s shot hit one of his teammates and went out for a goal kick.
The visitors were enjoying the majority of possession at this stage and Miller was next up to test the resilience of the home side’s backline.
The no. 9 found himself one on one with a defender and after beating his marker he knocked the ball past the advancing Kello but his cross was punted nervously to safety.
The Hearts keeper, who was in inspired form, then showed his agility by tipping an acrobatic overhead kick from Jelavic over the bar.
With no changes made to the teams for the start of the second-half it was Hearts who had a great chance to double their advantage but Kyle, who had acres of space at the back post, blazed his shot in to the stand.
The Light Blues recovered from this early scare and after the hour mark they had two great opportunities to get back in to the game.
On 66 minutes a rasping volley from Sasa Papac smashed off Kello’s left hand post.
And in the next attack, Davis played a great one-two with Jelavic to get in to the 18-yard box but his volley flew over the bar from 15 yards.
It was a great chance for the talented midfielder but with just eleven minutes left it was his international teammate Lafferty that netted a brilliant equaliser.
Laff, who had replaced Jelavic, stepped up to take a free-kick after Naismith had been brought down by Barr and his low, accurate shot gave Kello no chance.
The goal gave Rangers hope of collecting three points but with the game now flowing from end to end Kyle was guilty of missing a snip.
Craig Thomson delivered a teasing cross from the right and the big striker headed over from just five yards after using his height to soar above Whittaker.
With the clock ticking down and the ball now down the other end of the pitch Lafferty the saw a point blank shot saved by Kello before Davis hit the post with a superb volley.
A draw looked on the cards but with this phenomenal match moving in to injury time Rangers somehow found another gear and on 93 minutes they got their reward.
Lafferty played in man-of-the-moment Naisy who dipped his shoulder to get past a defender before finishing with aplomb.
It was a dramatic end to a great SPL clash but in the end Rangers showed the fighting spirit of Champions.