LAHORE - Pakistan opener Salman Butt claims to have found the key to success against Sri Lankan mystery spinner Ajantha Mendis after watching him bowl during the Indian Premier League trials for Kolkata Knight Riders. "He bowls like the typical finger tape-ball bowlers you find playing on the streets and his success comes from the fact that he has a very good faster ball without any visible change to his bowling action or grip on the ball," Butt said.Butt said he would now be more comfortable while facing the unorthodox off-spinner during Pakistan's upcoming series against Sri Lanka."At the end of the season, Mendis had appeared in trials for the Kolkata Knight Riders and I got a chance to watch him bowl and also played him in the nets," Butt said. "He uses his top finger to obtain speed off the surface and turn without changing his action," the opener added. Bowlers who use just two fingers to obtain turn and speed from tennis balls covered with tape in street cricket in Pakistan are described as tape tennis specialists. Mendis has been a runaway success since the Asia Cup held in Pakistan last year during which he bamboozled the batsmen with his variations taking six for 13 in the final against India in Karachi.