Lewis Hamilton is chasing history but has Red Bull on his tail

After an unpredictable 2020 Formula 1® campaign ended in wholly predictable fashion, the world's best drivers are back for more in 2021.

The coronavirus pandemic delayed the start to last season and prompted serious surgery to the planned race calendar.

At the end of it all, though, Lewis Hamilton and Mercedes again walked away on top of the pile.

As so often in recent years, the task for the rest of the grid this coming year is simply to stop the reigning champion and his Silver Arrow.

While that is easier said than done, of course, the signs in pre-season are promising.

Will testing preparations derail Mercedes in the opening weeks? We are about to find out, as the Bahrain opener is just days away...

MORE HAMILTON AND MERCEDES DOMINANCE?

Hamilton's title in 2020 was his seventh, tying Michael Schumacher's competition record. A new benchmark is on the horizon if the Briton can repeat his success.

That is not the only landmark in Hamilton's sights, either: with 95 wins and 98 pole positions – both F1 highs – he can surely look forward to a pair of century celebrations this year.

But even if this is to be another sublime season for the 36-year-old, he surely will not find it as straightforward as last year.

Hamilton shut out the noise surrounding his future to claim 11 victories in 2020, yet the new contract he belatedly signed at the end of the campaign keeps him with Mercedes only until the end of 2021.

That spells another 12 months of uncertainty for the sport's premier driver, who also does not yet appear entirely at home in the new W12 car.

The Silver Arrows recorded only 304 test laps in pre-season – the fewest of any team – and may require Hamilton and Valtteri Bottas to learn on the job if they are to extend their record-breaking streak of seven straight constructors' championships.

WHO CAN CHALLENGE THE DEFENDING CHAMP?

Mercedes team-mate Bottas has finished second to Hamilton in the past two seasons, but it would be a tough ask to expect him to outperform the 'GOAT' in the same car – even before considering potential issues with that machine.

No, if Hamilton is to be dethroned, Red Bull look the best bet.

Max Verstappen is undoubtedly the chief threat at the Austrian outfit, having qualified ahead of his team-mates on 36 of 38 occasions since Daniel Ricciardo departed (including a 17-0 record against Alex Albon in 2020).

Indeed, Verstappen – third last year – had the fastest lap time in testing, his effort of a minute and 28.960 seconds in Bahrain putting Red Bull on top in pre-season for the first time.

The Dutchman is pessimistic, though, saying: "[Testing] doesn't say anything about pure performance.

"I know people are excited and think we are just saying this, but Mercedes are still the favourites. How can they not be when they have won seven world championships in a row?"

Ferrari can never be counted out, but they are starting a season with two drivers yet to win a world championship (Charles Leclerc and Carlos Sainz) for the first time since 2007, when Felipe Massa and Kimi Raikkonen lined up for the Scuderia. Of course, that year ended with Raikkonen being crowned champion.

ELSEWHERE...

There is no shortage of intrigue away from the top teams, with two big names returning to F1 – albeit only one of the two drivers having previously raced at this level.

Former champion Fernando Alonso is back, joining the rebranded Alpine team, formerly Renault – where the Spaniard won two titles.

Alonso's most recent race win came in Ferrari colours at the 2013 Spanish Grand Prix, since when he has gone 110 events without victory.

If Alpine can be competitive and Alonso belatedly returns to the top step of the podium later in the season, he could break Raikkonen's record of 114 grands prix between triumphs (2013 to 2018).

The 39-year-old needs only three podiums to reach 100 in F1.

At the other end of the spectrum, Mick Schumacher is the familiar name but new face at Haas, forming an all-rookie line-up alongside Nikita Mazepin, his F2 title rival last year.

Schumacher, who won that championship, will debut at Bahrain eight years, four months and three days after father Michael's final race in Brazil in 2012.

Michael was also 22 when he made his F1 bow, although Mick will be seven months and 16 days younger.

Ricciardo has joined McLaren, who are 12 podiums shy of 500, and Aston Martin are back for the first time since 1960, replacing Racing Point and bringing in Sebastian Vettel.

Meanwhile, there will be increased attention paid to Williams' George Russell, who impressed when given a chance with Mercedes at Sakhir 2020, qualifying second and finishing ninth.