There's no argument now: Lewis Hamilton is a Formula 1 legend.

Five world championships - the last two won head-to-head against Sebastian Vettel - and 73 race wins have placed him firmly in the pantheon of the sport's greatest-ever drivers.

For good.

So, at the start of 2019, what is - or could be - next for the man who has already won it all?

When and how to watch the Australian GP on Sky

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Firstly, and most importantly, there's a fresh battle to try and win against established and emerging rivals - one Hamilton has already flagged up as the one likely to be Mercedes fiercest in his six years at Brackley.

"Ferrari are the fastest," said Hamilton at the end of winter testing. "This is going to be the toughest battle yet."

But there's a wider historical talking point at play too now for this generation's pre-eminent driver - Michael Schumacher's most prestigious all-time F1 records.

A remarkable 51 per cent win rate since the start of 2014 has propelled Hamilton into that statistical sphere, with the Englishman two world titles behind Schumacher's seven and just 18 wins behind the German great's benchmark of 91.

Hamilton has already taken over from the seven-time champion as the holder of F1's most pole positions and front-row starts, while he also holds the record for the most points scored in a season.

What could be next for Hamilton? World titles Schumacher 7 Hamilton 5 Race wins Schumacher 91 Hamilton 73 Podiums Schumacher 155 Hamilton 134 Races led Schumacher 142 Hamilton 129

With Mercedes themselves at the point where they are chasing history, with an unprecedented sixth title consecutive double in their sights this year, it's certainly an interesting way to frame the challenge ahead for world champion team and driver in 2019.

"You will have two groups; the ones that are cheering for our competitors, hoping that Mercedes are not going to achieve that, and then you will have a large group also that's going to say 'well, this is pretty exciting'," Mercedes boss Toto Wolff said at the start of the year.

"Are Mercedes going to be able to top Ferrari's record? Is Lewis Hamilton going to be able to match Michael Schumacher's record? It's another interesting angle of the Formula 1 narrative."

Why F1 2019 is huge for Vettel

What does Hamilton say?

Hamilton himself has played down talk suggesting he will now inevitably be focusing on Schumacher's records.

In fact, speaking at winter testing, the world champion said: "For me, it's not something that I allow my peers to talk about. That's not what we're here to focus on, that number."

Yet, consciously or not, closing on those landmarks is the obvious next consequence for a driver who strives to continue taking his own performances to the next level.

Take his pre-winter break request to his Mercedes team as a key example of that mindset, as he sought constructive criticism on areas he could still improve.

"I asked for my team to send me an email, from several different departments, and asked them to be blunt - they don't even need to tell me who the email's from," Hamilton explained.

"And just 'tell me the things you feel I can improve on, if there's been a certain experience this year you've felt that could be better, or something I said that's swayed the energy within the team'."

It's such self-reflection that makes Hamilton such a relentless and committed competitor, 12 years and more than 250 races into his Formula 1 career.

Hamilton and Mercedes' 2019 challenge: The pundits' view

Martin Brundle: "They always say they don't care about the statistics but it's not true, they do. They know the numbers and I'm sure Lewis Hamilton wants to leave the sport with a new high tide mark in every department in terms of statistics. To beat Hamilton and Mercedes over the course of a full season is a really hard thing to do, they've got the stamina and they seem to find extra speed and determination as the season unfolds. You wouldn't hesitate to put some money on Hamilton taking his sixth title."

Damon Hill: "This season is looking very much like it's going to be a very tough battle for Mercedes. They weren't the quickest in testing, but then testing is very much a phoney war. We won't really know until we get to Melbourne and, even then, we won't really know because it's a 21-race championship."

6:21 Former World Champion and Sky F1 pundit Jenson Button previews the 2019 season. Former World Champion and Sky F1 pundit Jenson Button previews the 2019 season.

When's the Australian GP on Sky?

Sky Sports F1 will be the home of live and exclusive Formula 1 in 2019, broadcasting all 21 races - including every practice, qualifying and grand prix.

And it all starts with the Australian GP this weekend.

The key times are:

* The race starts at 5.10am UK time on Sunday, simulcast on Sky Sports F1 and Sky Sports Main Event.

* Saturday's qualifying hour begins at 6am UK time, with build-up on Sky Sports F1 and Sky Sports Main Event from 5am.

* Coverage from Australia will start with the Live Melbourne F1 Launch Show at 5.50am on Wednesday.

* Thursday morning's Welcome to the Weekend show will be first broadcast at 7am on Thursday.

* The first track session of the year will be Practice One, underway at 1am on the morning of Friday.

Sky Sports F1 is the home of live and exclusive F1 - and new and existing customers in the UK can now get the channel for just £10 extra a month, our best-ever offer. Find out more here to watch the 2019 season live