Mumbai Indians face a do-or-die situation against Royal Challengers Bangalore in the first clash between two Indian Premier League sides in the Champions League Twenty20 in Durban on Sunday.

IPL runners-up side Mumbai Indians, led by Sachin Tendulkar, paid the price of inconsistent batting and bowling as they were stunned by less fancied sides in their first two matches.

They spanked underdogs Guyana by 31 runs in their third match on Thursday but are still unsure about a semi-final berth as only one spot remains open from Group B after South Australian Redbacks booked their place.

Mumbai Indians, Royal Challengers Bangalore and Highveld Lions -- who play Guyana in the other match on Sunday in Johannesburg -- are on two points each after a win. But Mumbai are at a disadvantage as they have played one more match than the other two.

Even if they win on Sunday, Mumbai Indians' chance of qualifying the semis will depend on the results of other teams.

On the other hand, RCB can still make it to the semi-finals even if they lose on Sunday and beat Highveld Lions on September 21 as they have the highest net run rate of 1.340 as against +0.529 of South Australia Redbacks and +0.260 of Mumbai Indians.

Mumbai Indians had promised a lot with their impressive IPL season but failed to click as a unit in their first two matches and a Kieron Pollard's special effort saw them win the third against Guyana on Thursday.

Batting woes did them in, in the first match as their star-studded line-up failed to chase down 187 against an inexperienced Highveld Lions in a shock result in the tournament opener.

The willow wielders made amends in the second match against South Australia Redbacks by posting 180 for seven but the listless fielding and bowling meant that they failed to defend the big total and with that their CLT20 campaign had gone haywire.

Except for Sri Lankan Lasith Malinga, who has bagged six wickets by conceding 83 runs in the three matches, none of the Mumbai Indians bowlers have made a mark and that has been the main reason for the side's struggle in this tournament.

Zaheer Khan and Harbhajan Singh have been disappointing so far in the tournament. Zaheer has taken just one wicket by conceding 105 runs in the three matches while Harbhajan has scalped two at the expense of 86 runs.

RCB began the tournament with an easy nine-wicket win over Guyana with South African Jacques Kallis starring with both, bat and ball.

They were, however, brought back down to earth, with a humiliating eight-wicket loss to South Australia Redbacks on Friday.

Without Kallis, the Anil Kumble-led side failed in both batting and bowling as they were shot out for 154 and then none of their bowlers, including the captain himself and South African Dale Steyn, making much impact against the Australian side.