Mumbai Indians will clash with Perth Scorchers in their must-win final Group-A match of the Champions League Twenty-20 cricket tournament at the Feroz Shah Kotla Stadium in New Delhi today.The match will begin at 4 PM. This year's IPL winners Mumbai must beat Perth with a big margin, if they wish to book a semi-final berth.Rajasthan Royals, who had already sealed a semi-final slot from Pool-A, yesterday defeated Otago by 4 wickets, bolstering Mumbai's chances of making it to the semis.At present, Rajasthan is at the top of the points table in Pool-A, with Otago at second and Mumbai at third.In today's other match, Chennai Super Kings will meet Trinidad and Tobago in the Pool-B fixture at 8 tonight. This match will also be played in Delhi.Chennai have already made it to the semi-final and are at the top in Pool-B. The fate of the second team will be decided with today's result, as Titans are also in contention for a semi-final berth.The semi-finals of the competition will be played on Friday and Saturday, with the title clash slated for Sunday.