Malinga picked up four wickets, all of them clean-bowled, as Somerset fell to 150 for eight replying to Mumbai Indians' 160 for five. In the final Sunday, Mumbai take on Royal Challengers Bangalore.
A half-century (62) by Craig Kieswetter put Somerset in sight of a possible victory, but seamer James Franklin delivered a double strike in the 19th over to set the stage for a similar performance in the 20th by Malinga who added two more to the two he had taken at the start of the innings.
Image: Mumbai Indians' bowler Lasith Malinga, left, celebrates the dismissal of Somerset batsman Peter Trego, right, during their Champions League Twenty20 cricket semifinal match in Chennai, India, Saturday, Oct. 8, 2011. Mumbai Indians won the match by 10 runs.