By Gabriel TanFollow @@gabetan13
In a game that was largely dominated by the Thai Premier League outfit, Roar goalkeeper Michael Theo looked set to emerge as the hero at the Thunder Castle Stadium after he made a series of outstanding saves to keep Buriram at bay for the entire 120 minutes.
However, it was his opposite number who proved the difference in the end as Sivaruck Tedsungnoen made three smart saves in the shootout to deny Thomas Broich, Besart Berisha and James Meyer, which was enough to send his side through after Osmar Barba, Charyl Chappuis and Jirawat Makarom all converted their spot-kicks.
Attaphol Puspakom's charges now head into Group E, where they will face off against K-League champions FC Seoul, Chinese Super League outfit Jiangsu Sainty and Vegalta Sendai of Japan.
Although it was a deserving result given Buriram had undoubtedly been the better side for the majority of the game, it was the A-League side who actually began the brighter and they could have taken the lead after just eight minutes when Ben Halloran found space down the right and cut the ball back to Stef Niljand, who was just unable to control his shot.
Nonetheless, the hosts gradually found their groove and Theo had to be alert seven minutes later when he raced off his line to smother at the feet of Ekkachai Sumrei, who had looked poised to race through and fire a shot away.
In a lively start to the game, Roar were next to have an effort on goal in the 25th minute when Luke Brattan let fly after picking up possession 30 yards out, but Sivaruck did well to danger as the ball bounced dangerously in front of him.
But that proved to be the last time the visitors would pose a threat for the remainder of the first half as Buriram began to dominate proceedings, with Theerathon Bunmathan proving a real threat from set-pieces.
Three minutes before the half-hour mark, he intelligently drilled a corner to the waiting Chappuis, who struck a firm effort from the edge of the box that sailed just wide of the top corner.
11 minutes later, Theo was called into action once again when he produced a smart save to deny Kai Hirano, who had cut in from the left and fired in a fierce shot that looked destined for the bottom corner.
A minute before the break, the Thunder Castle came even closer to finding the breakthrough when sloppy play from Brisbane handed the ball to Theerathon, who immediately threaded the ball through to Anthony Ampaipitakwong. With Jade North in close attention, the 24-year-old did well to get a first-time shot away only to see it flash just wide of the post.
Five minutes into the second half, Roar almost made the hosts pay for their failure to convert when Broich pounce on a rare moment of indecision in the opposition backline and forced his way in between Suree Sukha and Osmar before poking a shot towards goal. Sivaruck did well to get his body in the way but the loose ball fell invitingly into the path of Mitch Nichols, only from him to blaze his shot way over.
Three minutes later, Theo was once again required to keep the scores level when he produced a flying save to keep out a 35-yard piledriver from Surat Sukha, and shortly after, the 31-year-old did well to prevent a tantalising left-wing cross by Ekkachai from reaching Hirano.
With their opponents firmly in the ascendancy, Roar desperately needed to get into the game if they were to keep alive their continental hopes but a minute after the hour mark, they almost netted against the run of play when Niljand broke free down the left after a sweeping counterattack but could only fire wide from 15 yards out.
Ekkachai, who was beginning to cause real problems for Roar substitute Jack Hingert down the left, then delivered another good delivery into the box in the 72nd minute to pick out Osmar but, having done the tough bit in getting ahead of his marker, the Spaniard failed to get enough on the ball to divert it towards goal.
A minute from the end, Buriram had one final chance to grab the win in regulation time when substitute Goran Jerkovic was left in acres of space on the edge of the area, but he screwed his effort way wide after bringing the ball down sublimely on his chest.
For the entire 90 minutes, the hosts had done an excellent job of keeping the dangerous Broich quiet, but three minutes into extra-time, he nearly carved them open when he broke free down the left and floated the ball into the box, but Sivaruck did well to punch it clear before either of the Roar strikers could pounce.
Six minutes later, the German midfielder went on another rampaging run down the left and into the middle before drilling in an effort, but he again could not find a way past the Thunder Castle custodian, who repelled his strike with a flying save.
By now, it was beginning to look as though the first team to find the breakthrough would go on to win the game, and Buriram could have done just that in the 103rd minute when an awful back-header from Hingert sent Suchao Nutnum racing through down the left.
The Thunder Castle skipper, who had started the game on the bench, advanced on goal before effortlessly sliding his shot past the onrushing Theo, only for it to agonisingly trickle just wide of the far post.
A minute later, Jerkovic had a chance of his own when the ball dropped to him just inside the area, but his blistering half-volley was smartly parried away to safety by the opposition goalkeeper, who by now was the frontrunner for man-of-the-match honours.
And just as the clock ticked into the 120th and final minute of the game, Suchao found space down the left before cutting the back back to Chappuis but - with a sliding effort at full stretch - the 21-year-old could only steer the ball wide.
Moments later, referee Kim Dong-jin blew for fulltime, sending the tie to the dreaded shootout, where Sivaruck eventually emerged as the match-winner as he first made an outstanding one-handed save to deny Broich, before guessing right to keep out tame efforts from Berisha and Meyer.
Buriram had no such problems as Osmar, Chappuis and Jirawat all clinically found the back of the net, sending their side through to the group stage of the Champions League for the second season running.
Buriram United: Sivaruck Tedsungnoen, Suree Sukha, Pratum Chutong, Osmar Barba, Theerathon Bunmathan, Charyl Chappuis, Surat Sukha, Anawin Jujeen, Ekkachai Sumrei (Suchao Nutnum 90'), Anthony Ampaipitakwong (Jirawat Makarom 102'), Kai Hirano (Goran Jerkovic 81').
Brisbane Roar: Michael Theo, Ivan Franjic (Jack Hingert 36'), Jade North, James Donachie, Shane Stefanutto, Ben Halloran (James Meyer 116'), Luke Brattan, Mitch Nichols, Thomas Broich, Stef Niljand (Steven Lustica 114'), Besart Berisha.