Australia vs South Africa: Why Starc and Jansen should be in the firing line

Australia are the second-quickest starters with the bat, and the second-most miserly starters with the ball. South Africa have been slow starters with the bat - even slower than Pakistan and Afghanistan - but explosive with the ball, taking more powerplay wickets than any other team. South Africa have recent form on their side, having beaten Australia in their last four encounters, including once in the group stages of this World Cup. Australia, though, have the momentum of having won seven matches on the trot, plus some knockout ghosts to remind South Africa of. These are some of the tactical moves to watch out for as they face off in Kolkata.

What to do at the toss?
No secrets there. South Africa want to avoid chasing, and Australia want them to chase. Even when winning against Pakistan and Afghanistan when chasing, they huffed and puffed their way through. All their four recent wins against Australia have come batting first.

There might be some respite for South Africa though. There is a forecast for some rain in the evening. If this forecast convinces Australia to chase or cuts short the duration of South Africa's chase, it could mitigate South Africa's chasing troubles.

Still, expect both sides to risk the dew or the rain because the advantage to be gained by batting first is too big to ignore.

Weighing up team combinations
Unlike India and New Zealand in the first semi-final, these teams have one selection doubt each. Australia have to choose between Marnus Labuschagne and Marcus Stoinis. Labuschagne brings more solidity to the middle after the explosive top three whereas Stoinis in theory brings both powerful hitting lower down the order and a sixth bowling option. Current form - and indeed sentiment - is with Labuschagne, especially with some solidity required in the middle overs, but expect Australia to play him only if they are confident in Travis Head and Mitchell Marsh helping out with the ball as their fifth bowler is Glenn Maxwell. Also, Labuschagne's record against left-arm spin can go against him because he will have to face a lot of Keshav Maharaj in the middle.

South Africa played Tabraiz Shamsi in their league game in Kolkata. Shamsi didn't have a great game, but they did read the conditions well: there was enough in the pitch for him and other spinners. This will be a conditions-based toss-up between Shamsi and Gerald Coetzee, the latter bringing some hitting lower down the order.

Put pressure on Starc
Mitchell Starc hasn't had many chances to bowl with a moving ball this World Cup, which partly explains his economy rate of 6.55 and average of 43.9. It hasn't swung or seamed much in Kolkata either. So, especially if they are chasing, South Africa might want to target Starc because we have seen that generally if you fall behind in a chase this tournament, there is no way back.

Maxwell before Zampa?
In his last three matches against South Africa, Adam Zampa has averaged 63.25 and gone at 8.43 an over. Expect Australia to go to Maxwell before Zampa not least because Quinton de Kock hasn't quite liked offspin of late. His strike rate against offspin this World Cup has been 78.37; his release shot against them, the reverse-sweep, has got him out twice in six attempts.

The problem for South Africa is that Temba Bavuma has even worse numbers against offspin. If there does come a situation where de Kock is stuck against Maxwell, they will need Rassie van der Dussen and those following to compensate.

Reverse-swing on the cards
South Africa's plan has been to start steadily and keep constantly accelerating. They have been the most explosive side at the death. However, do remember that Pakistan found reverse in Kolkata. That means the square is dry. Getting the old ball going will be a must for Australia if they don't take early wickets.

South Africa will look for the same if they end up bowling first. So watch out for a lot of cross-seam bowling, and umpires stopping fielders from returning the ball on the bounce.

Target Jansen
Marco Jansen has been one of the big reasons South Africa have been successful in this World Cup. Even when he is not swinging the ball, his height gives him a big advantage. However, there have been two games where he has gone for more than 90. Once when Kusal Mendis got stuck into him, and once when he started waywardly, possibly out of nerves, and then Rohit Sharma took advantage.

The trends suggest that Jansen is a handful if he gets into his groove. Australia will likely want Head and Marsh to go after him and see if he cracks, while David Warner bats normally at the other end. The first ten overs of Australia's innings promise to be delicious either way.

Maharaj key in the middle
South Africa will hope that the quicks have got past the top three by the time they introduce Maharaj because Steven Smith and Labuschagne don't quite prefer left-arm spin. Ravindra Jadeja got them both out in Chennai, and Mitchell Santner managed to shut them off