Cricket: The key match-ups

David Leggat looks at the four crucial areas which could decide tonight's quarter-final

Opening batsmen

Graeme Smith and Hashim Amla vs Brendon McCullum and Martin Guptill

The South African captain has had an ordinary tournament, only 155 runs at 25 from six innings, and hasn't looked particularly convincing. By contrast Amla, who has cricket's most distinctive beard, has been in prime form, with 299 runs at 49.

McCullum and Guptill have made solid runs, sharing an unbeaten 166 in the 10-wicket win over Zimbabwe and have had two other opening stands above 50, balanced by three under 30. Must get the innings off to a secure start.

The middle order

Jacques Kallis and AB de Villiers vs Jesse Ryder and Ross Taylor

There's a case to be made for de Villiers, assuming he's over his thigh injury, being the best ODI batsman going around. His 318 runs from four innings give him an average of 106 in the Cup. Only Kumar Sangakkara and Michael Clarke have higher averages.

De Villiers scores at a run-a-ball rate and is adept at working most situations to South Africa's advantage. Kallis has been relatively ordinary with the bat, but his record, 45.44 over 313 ODIs with 17 hundreds, suggest he's due a score.

Taylor is New Zealand's top scorer, with 245 runs at 81.66. Might his hundred against Pakistan and spanking of the Canadians suggest he's seeing the ball well right now?

Ryder has had only three innings, 25, 38 and 19, not being required in the 10-wicket wins over Kenya and Zimbabwe, and missing the Pakistan game with illness. New Zealand need these two to step up.

The spinners

Johan Botha/Imran Tahir and Robin Peterson vs Dan Vettori and Nathan McCullum

The tight-fisted Botha has replaced the exotic legspinner Imran Tahir, who fractured a finger after taking 12 wickets in the first four games. But Tahir is fit again and will be a threat.

Botha can be relied upon to keep things tight, but without Tahir's penetrative qualities. Left-arm orthodox Peterson has 14 wickets at the tournament, third equal with Tim Southee and Umar Gul, and opened the bowling with considerable success against England.

He also took four for 12 in the demolition of Bangladesh at the Shere Bangla Stadium so he's had recent success at tonight's venue.

Vettori has been sidelined for the last two games with a knee injury but is expected back tonight. How New Zealand need him. One of the best ODI operators going around with a dozen variations in line and pace, and his batting will be handy.

McCullum's not a big wicket-taker but can tie up an end, fields brilliantly and is among the best lower-order hitters in the Cup.

The new ball

Dale Steyn and Morne Morkel vs Tim Southee and ...

Steyn and Morkel represent perhaps the game's best new ball pair since Pakistan's disgraced Mohammad Asif and Mohammad Aamer were run out of the sport. Steyn is quick, accurate and always at the batsman. The lanky Morkel is lively and awkward with his height. A tough pair to combat.

Southee has had a fine tournament, with 14 wickets at 15.07 apiece. Only Shahid Afridi (21) and Zaheer Khan (15 before last night) have taken more than a player whose development has been in giant-sized strides this season.

Who gets the other end? If Kyle Mills' thigh is okay, he does his best work with the new ball. Otherwise, it's Daryl Tuffey in as Hamish Bennett's replacement.

He'd relish a belated opportunity but the other alternative is opening with a spinner, Dan Vettori or Nathan McCullum. After all, it's been done before.