Cape Cobras beat New South Wales by seven wickets in their Champions League Twenty20 Group B match at M A Chidambaram stadium Chennai on Saturday.Earlier, electing to bat, New South Wales scored 135 for eight. Cobras achieved the target in 17.2 overs for the loss of three wickets.In another encounter, Chennai Super Kings captain Mahendra Singh Dhoni won the toss and elected to bat first against Mumbai Indians in their Champions League Twenty20 opener at Chennai on Saturday evening.