Firdose Moonda
Cricinfo writer on BBC Radio 5 Sports Extra

The little moments define the big moments. If South Africa don't start off well it works in Australia's favour.

Sir Alastair Cook
Ex-England captain on BBC Radio 5 Sports Extra

There's not much grass, no indentations or massive cracks.

It's nipped just enough, it's been a normal Lord's wicket.

Do you think the match will be decided today? What sort of total can South Africa chase? Who will be the key players?

As ever, do get in touch to let us know your thoughts on the action. And don't be shy - pop your name at the end of your message!

Firdose Moonda
Cricinfo writer on BBC Radio 5 Sports Extra

If South Africa win, it will change everything. It will change the perceptions about them, how they respond to pressure and what they do in big moments.

They're inexperienced guys without big superstars, particularly batting superstars.

BBC Test Match Special

You can follow ball-by-ball coverage of day three with Jonathan Agnew and co on Test Match Special.

Click on the 'listen live' button at the top of this page or find BBC Radio 5 Sports Extra in BBC Sounds.

If you missed any of day one or two at Lord's, I'm afraid you've got a lot to catch up on.

A total of 28 wickets fell across the first two days, with both South Africa and Australia suffering batting collapses and bowlers Kagiso Rabada and Pat Cummins each adding their names to the honours board.

Australia are 144-8 in their second innings, with a lead of 218 runs.

Image source, Rex Features

Hello there!

Welcome along for day three. Will today be the day that the winner of the World Test Championship is crowned?

Last night Vic Marks said we're in for an "old-fashioned treat of Test cricket" at Lord's, so lets get cracking!