New Zealand's deadly tag team

There's a gentle cadence to a Tim Southee-Trent Boult dual spell. One swings the ball away, the other brings it in. A right-armer and a leftie, both tall, sharp and slim. They're each sleek in their approach too, no wasted energy, no vortex limbs. Through the crease like stones skipping over water. By the time the ball reaches the other end, the batsman is dodging a grenade.

Day two's Hagley Oval crowd wasn't quite the 8000-strong bumper crop from the previous day. They saw nothing as historic as a 134-ball 195. But throughout the morning and just after lunch they watched the game so closely that they were practically inhaling the action. This is no ordinary New Zealand team, they know now. It is a team whizzing around the planet, counting off deflated oppositions and bested foes. New Zealand were imposing with bat in hand on day one, but perhaps the Hagley crowd realises that their team never seems more potent than when two quick bowlers, 25 and 26, are laying waste to oppositions, from either end.

The team knows it too, so they field like demons in the early overs. No run, or quarter given freely. It's athletic intimidation. No glares or sledges required. Trees on the ground's periphery, grass on the pitch, Asian batsmen swaddled in sweaters, fidgeting between balls; New Zealand are in their element. The slips, who cover practically every inch from the keeper to point, so good are the gully fielders, is more a fortress than a cordon.

Boult, the more suave of the two, began Sri Lanka's innings with a ball well wide of off stump, to show the batsman the swing. The next ball to Dimuth Karunaratne was eight inches closer to the stump, moving deliciously late, like someone in the slip cordon was holding a ball-magnet. If this over had a soundtrack, the big, ominous drum would have already begun, because the dismissal next ball almost seemed inevitable. Another big banana, shaping away, but pitching in line with the stumps and hitting off, if the batsman's front pad hadn't been in the way.

At the other end, Southee wasn't outdone for swing, or control. Kaushal Silva, the only right-hander in the Sri Lanka top four, kept stabbing at balls going away for him, desperate to get a left-hander on strike. "You deal with him, I've got Boult covered," he seemed to be saying. Until a piece of inspired inswing bowling, straightening a surprise delivery down a leg stump, from Boult nailed Kaushal too; the batsman offering no stroke, then reviewing - his mind still not caught up with the swindle Boult had pulled off.

When Boult had Sangakkara caught well at third slip he sought out Southee in the huddle, flashed a smile and gave him a pat on the backside. "It's me today," he seemed to say, "but it could just as easily have been you." It has often been said that Boult and Southee complement each other, but that is clearly also a double entendre, because when they face the press, the two can't stop talking each other up.

"It's all about bowling partnerships in our eyes and if one is bowling well and the other is taking the wickets, we're perfectly happy with that," Boult said of bowling opposite Southee, at the end of day two. "Even as a unit that's the motto. The glory doesn't go to one person, it's a team job and we're all doing it well. Everyone deserves credit for what happened."

They are no longer just bright prospects now. Both 100-wicket bowlers, theirs is a partnership that will soon rival Dale Steyn and Morne Morkel, or James Anderson and Stuart Broad. Unlike the other pairs, they are not spearhead-and-enforcer, but twin threats of equivalent style and ability. Within minutes of an opposition innings' beginning, their spells melt together in the mind. Symmetry and synchronicity pulled together with a simple, repeatable method. When Boult is playing, Southee's bowling average dips by over five runs. For Boult, Southee's presence betters his average by about two.

"Bowling well is about starting well and building pressure," Boult said. "Not trying to search too much and think it's all going to happen like it did early today. It's looking for that assistance, swinging the ball and getting it to move from the wicket."

Shane Bond, the man who fully weaponised these two, often watches from beyond the boundary at long off. On a day like Saturday, he is less combing for flaws, more admiring his handiwork. He was through the crease like silk too in his prime, but he never had a partner-in-crime like his pupils do. Even at this age, Boult and Southee have already played many more matches, and claimed more scalps.

Southee and Boult thrive on swing, seam and accuracy for now, but before long they will have to add more arrows to their quiver, say on tours of India or Australia. Brendon McCullum, Kane Williamson and Ross Taylor are coming into their own too, in this New Zealand team, but in Boult and Southee, New Zealand have one of the great cricket partnerships in the making.