Australian Open Tennis Championships : AO Analyst: Williams v Kerber

It's almost not the same sport.

Serena Williams and Angelique Kerber are polar opposites in how they go about their craft.

Kerber, seeded seventh, has advanced to the 2016 Australian Open final with an emphasis on consistency, patiently building control of the point as rallies develop.

It's worked marvellously well for her, only dropping one set for the tournament, in the opening round to Misaki Doi.

Slice a lefty serve, stay solid off the backhand, and get a little more creative with the forehand.

Kerber has played 51 per cent (423) of her points in the 'first strike' 0-4 shot range, 27 per cent (228) in 5-8 shots, and a substantial 22 per cent (186) of her points in extended rallies of 9+ shots.

Kerber enjoys longer rallies. There is just one major problem. Williams doesn't.

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The style of play that got Kerber to the final will absolutely not be the style that she will get to employ to win it.

While Kerber has played 186 rallies of at least nine shots, Williams has played - wait for it - just 25.

Kerber has wonderful shot tolerance. Williams has no tolerance for hitting shots.

Consider what Williams did to Agnieszka Radwanska's desire to extend the rallies in their semifinal. In the two rounds before the semis, Radwanska averaged 39 9+ rallies per match. Against Williams, there were only seven.

There were only three 9+ rallies in Williams' quarterfinal match against Maria Sharapova.

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In the fourth round, Williams defeated Margarita Gasparyan 6-2, 6-1. Gasparyan played 31 rallies of 9+ shots in her previous match against Yulia Putintseva. There were only four against Williams.

This is the recurring nightmare that Williams forces on her opponents.

They all want to rally. They all don't get to rally.

The best way to prepare against Williams is to hire a ball machine that also hits serves. Set the speed to 174 kph (108mph), which is Williams' average speed the past two weeks, and don't come off the court until you can handle the heat.

Also, every now and then crank the speed up to a frightening 202 km/h (126mph), because Williams can also go there as well.

The next thing to practise is someone poleaxing returns right at you. Hit a serve, and then just as you are finishing your follow through, get ready to hit the next ball.

It comes back that fast.

No matter what Kerber wants to do in this final, she will be the one reacting to what Williams allows her to do.

Kerber should not rely on winning too many points against Williams' first serve. Williams has made 167 first serves for the tournament so far, winning 139. That's 28 first serves lost in 12 sets - or just 2.3 per set.

That adds up to Williams winning a tournament best 83 per cent of her first serve points - exactly the same as Milos Raonic, who leads on the men's side.

There is no obvious advantage Kerber has anywhere on the court. Kerber will not be allowed to play points on her terms. Williams will do the exact same thing she does every day.

Can Kerber win? Yes she can. They have played six times, and Kerber beat Williams in the quarterfinals of Cincinnati in 2012, 6-4 6-4. In the other five matches, she has not won a set.

Kerber must accept the fact that rallies will be lightning quick, while at the same time, still trying to make Williams hit one more ball.

Kerber has converted 43 per cent of her break points to the final. The tournament average is 44 per cent. This will have to be close to perfect against Williams, as she may only get one or two opportunities in a couple of sets to seize the day.

A bright spot for Kerber is that she is making 88 per cent (377/429) of her returns for the tournament, much higher than the tournament average of 79 per cent.

Something has to give here, as Williams is averaging 40 per cent of all serves unreturned.

Williams is a prohibitive favorite. The match still needs to be played.

Maybe Kerber's lefty angles will create concern for Williams. Maybe rallies will get extended more, where Kerber can stretch Williams out to the edges of the court.

Williams does a lot of things unbelievably well, but the ability to completely take her opponents out of their comfort zone must be up around the top of the list.

Craig O'Shannessy is the lead strategy analyst for the ATP Tour, and the 2015 USPTA Tour Coach of the Year.