Celtic effectively put the Scottish Premiership title beyond the reach of Rangers after coming from behind to beat Hearts 4-1.
The victory put Celtic nine points and 22 goals ahead of Rangers, who have three games left starting with Sunday's Ibrox clash with Dundee United.
Only an unprecedented collapse could prevent Celtic officially confirming their 10th title in 11 seasons before or after their final two cinch Premiership games against Dundee United and Motherwell.
The Celtic Park crowd were not waiting to celebrate as they hailed the achievements of Ange Postecoglou and his players, who lost their first three away games of the campaign before embarking on an unbeaten league run that stands at 30 games.
Ellis Simms threatened to spoil the party when he fired Hearts into an early lead but Celtic turned the game around before half-time in controversial fashion through goals from Daizen Maeda and Kyogo Furuhashi.
Matt O'Riley's goal midway through the second half put the game and the destiny of the title beyond doubt and substitute Giorgos Giakoumakis got in on the goalscoring act.
Hearts started on the front foot and took the lead inside three minutes as Simms lashed home from 12 yards after Liam Boyce had helped on Alex Cochrane's cross. Carl Starfelt appealed for offside as he failed to cut out the flick-on but his trailing leg was probably playing Simms on.
The on-loan Everton forward had a chance to add to his tally but Josh Ginnelly's cross was inches too high and he could not get enough power on his header to beat Joe Hart.
Celtic pushed forward and Craig Gordon made an excellent stop from David Turnbull before saving Furuhashi's header. Turnbull then teed up O'Riley but the midfielder's effort was headed clear by Stephen Kingsley.
Despite the pressure, there was an audible anxiety among the home fans when moves broke down.
The home nerves calmed on the half-hour mark when Jota burst through the Hearts back line on the counter-attack and squared for Maeda to sweep home.
The visitors complained strongly to referee Don Robertson that Toby Sibbick had been fouled by Celtic skipper Callum McGregor when possession was turned over.
There were more arguments as Celtic went ahead seven minutes later.
Gordon scooped away Furuhashi's header after Jota had headed O'Riley's cross across the goal line but assistant referee Dougie Potter signalled for a goal. Television replays vindicated his decision.
Celtic could have moved clear before half-time but Gordon saved from O'Riley's free header.
Maeda failed to make the most of two chances early in the second half and O'Riley struck the inside of the post from 18 yards.
The tension reappeared as Hearts came back into the game and forced several set-pieces but the atmosphere was transformed in the 69th minute.
Jota was involved again, bringing down a high ball and feeding Greg Taylor's overlap. The left-back's deep cross was taken down by O'Riley and the midfielder side-footed the ball inside the far post.
Celtic Park went into celebratory mode and James Forrest and Reo Hatate came close to further extending the goal difference advantage before Giakoumakis fired home the fourth in the last minute following Forrest's cutback.
