From the moment the Sydney Sixers tossed the ball to mystery spinner Sachitra Senanayake at the Gabba last night, the Brisbane Heat found themselves guessing. The little-known Sri Lankan completed an opening maiden, then bowled a dozen balls before conceding a run, and the Heat were on their way to a sub-par total of 6-127, with only Luke Pomersbach (37) putting up any stern resistance. It was the Heat’s lowest completed total in the BBL and never enough on a dry pitch, even if the Sixers had a few wobbles before winning with an over to spare and five wickets in hand, breathing some life into their finals hopes at the same time. Senanayake has a colourful past to say the least. The right-arm spinner has played seven ODI’s for Sri Lanka but wasn’t included in their squad to play the Australians this summer. In 2011, he was reported for having a suspect action during Sri Lanka’s ‘A’ tour of England and duly sent home, where he underwent a training program with the country’s coaching unit to correct any trigonometric deficiencies. There may have been a few raised eyebrows in the Gabba stands but suspect actions weren’t up for discussion last night. Pomersbach was still trying to work out who the guy was and where all the trick deliveries were coming from. Senanayake finished with 0-19 off his four overs and opened the bowling in combination with Stephen O’Keefe (3-21), forming a twin spin spearhead for the first time in BBL history. It kept the Heat firmly in the blocks. James Hopes faced eight balls then went for a duck and while Pomersbach eventually got moving, the damage had largely been done. “It was a bit different, especially at the Gabba. You might expect to see one spinner but not two. It was pretty good tactics by them I thought,” Pomersbach said. The big left-hander admitted he had never heard of or seen any work from Senanayake and had to try to play the varying deliveries – and there were a few – on their merits. “He was quite tough to face, the Sri Lankan. He bowled really well, changed it up. It’s hard to face someone who bowls so many different balls in an over,” Pomersbach said. “I’d never faced him, never heard of him, never seen him. He’s done a good job for him tonight. “I thought I’d just watch the ball and hope he’d bowl me some bad stuff up front. He didn’t bowl me too many.” A subsequent collapse saw the Heat lose 4-13 in the face of tight and controlled Sixers bowling that only provided one extra, courtesy of a Brett Lee wide late in the innings. Brisbane started with a spinner of their own in Nathan Hauritz but the result wasn’t the same, with Brad Haddin taking the former Test tweaker for a four and a six to give his side a flying start. With man-of-the-match Michael Lumb (61 not out) in control, the Sixers looked in complete command before new Australian ODI paceman Ben Cutting put on the brakes in the 12th over. Curiously, Cutting was the sixth bowler used and returned 2-9 from his three overs. He didn’t get time for a fourth as Lumb hit the winning runs off Kemar Roach with an over to spare. Last year's BBL champions the Sixers remain in sixth spot on six points on a congested table but their convincing win gave a massive boost to the net run rate. The final round has a number of top-four contenders playing each other and a third straight Sixers’ win - against the pacesetting Melbourne Renegades, who will be without Aaron Finch, at the SCG on Wednesday night - could see them defend their title. The Heat need results to fall their way to have any hope of playing in the finals. If the Melbourne Stars beat the hapless Sydney Thunder tonight, it’s another season gone.