Sri Lanka's new Twenty20 hero Ajantha Mendis has revealed he is grooming a new weapon to add to his already flourishing spin artillery.Mendis spun his nation to victory over Australia by eight runs on Monday, with the first six-wicket haul in the game's shortest format.But the 26-year-old - who bowls both off- and leg-spin - warned the world's batsmen that he is developing another delivery, coming to the international scene soon."I am developing a new ball but I haven't still tried it. Hopefully it will come out soon," Mendis said."I am very pleased to know that my effort is a world record. I didn't realise it was one. I really enjoyed what I did today (Monday) and I am sure that it will give me confidence."I just wanted to bowl a good line and length and that worked off. The wicket also helped me a lot.Mendis admitted, somewhat ironically, that his aim was to reduce Australia's run-rate, rather than cut through their order, when his captain Tillakaratne Dilshan threw him the ball in Pallekele on Monday."I didn't want to give too many runs. We were trying to limit the runs more than pick up wickets. We had a plan and we bowled according to that plan," he said."I mixed up my deliveries and I thought the catch Angelo Mathews helped take changed the complexion of the game."Mathews had earlier helped dismiss Australian opener David Warner for Mendis' second wicket by catching him on the boundary, but knowing he was about to step over the rope, he threw the ball to team-mate Mahela Jayawardene to complete the catch, and save six runs at the same time.In other Sri Lankan news, paceman Lasith Malinga will miss their opening one-day international against Australia on Wednesday in Pallekele, as he continues to recover from a back injury.Chariman of selectors Duleep Mendis said Malinga will be considered for the remaining four ODIs in the series, with the second match scheduled for Sunday in Hambantota.