Champions League scenarios, Group B October 4, 2011

Knight Riders must pray for rain

The semi-final scenarios for group B

With just two matches left, all five teams still have a theoretical chance of making the semi-finals, but Kolkata Knight Riders will need divine intervention to qualify for the knock-out stage. Here's what each team needs to do (and what they need other teams to do) to make the last four.

Royal Challengers Bangalore's emphatic victory on Monday means that Kolkata Knight Riders are now depending on the weather gods to make further progress in the Champions League Twenty20. Royal Challenger's 51-run victory - the biggest margin of the tournament so far - has boosted their net run rate to +0.438, well clear of Knight Riders' +0.306. This means that whatever Royal Challengers' margin of victory against South Australia on Wednesday (assuming they win), it'll still ensure that their NRR remains above that of the Knight Riders. On the other hand, if South Australia win, they'll jump up to five points, which is more than Knight Riders' four.

If that game is washed out, though, South Australia will move to four points, but their NRR is much poorer than the Knight Riders', while Royal Challengers will remain on three. That will be the best chance for the Knight Riders to sneak through.

At least one of the two other teams playing on Wednesday - Somerset and Warriors - will go past Knight Riders on the points table regardless of the result. A win for either team will push that side ahead, while a washout will take Warriors to five points. There's also the possibility of both teams being ahead of the Knight Riders, if Somerset win by a small margin (for instance, if they score 140 and win by fewer than eight runs).

For the other teams, the equation is now fairly clear:

Warriors need a win to be certain of a semi-final slot. If they lose, they'll have to hope that their margin of defeat is tiny, so that their NRR doesn't fall too much below its current +0.592. In such a case, if Bangalore win by a very small margin, their NRR will stay below that of Warriors, and Somerset and Warriors will make the semi-finals.

If their game against Somerset is washed out, then Warriors will be certain of making it to the last four regardless of the result in the other match.

South Australia's problem is their dismal NRR of -0.775. Nothing less than a win will do for them. If they win, though, they'll be assured of a semi-final slot regardless of the margin of victory or the result in the other match.

Somerset's position is exactly the same. Their heavy defeat against Royal Challengers has brought down their NRR to -1.133. A win will take them through, a defeat or a washout will end their tournament.

Royal Challengers Bangalore have an excellent chance of qualifying if they win, for their NRR will stay above that of the Knight Riders. Warriors have a better NRR, though, and if they lose to Somerset by a small margin, it's possible that they'll stay second in the table if Royal Challengers have a very tight victory.

The margin of the result on Monday has brought Royal Challengers right back in the mix. All they need now is for a similar performance on Wednesday, and for the Bangalore weather to stay clear.

S Rajesh is stats editor of ESPNcricinfo. Follow him on Twitter