Lewis Hamilton and Max Verstappen lead Formula One into a new era in Bahrain this weekend as the sport seeks to move on from one of its most controversial seasons with a fresh start and plenty of change.
New-look cars, heavier and with bigger wheels but re-drawn aerodynamics to make overtaking easier, have raised hopes of a general shake-up as part of the most far-reaching overhaul in decades.
Michael Masi, the race director whose decisions left Hamilton feeling robbed of a record eighth title in the Abu Dhabi showdown last December, has gone, while Mohammed Ben Sulayem has replaced Jean Todt as head of the governing FIA.
While last year's title contenders will be renewing their fierce rivalry, the battle looks set to stretch beyond a private duel.
"I think there's going to be a real mix of pecking order through the year in all likelihood. The development rate is going to be very aggressive," said McLaren technical director James Key.
"There's a chance people will surprise, and people will be a little bit further back than expected in the first races."
Champion Verstappen, 24, will start the season at Sakhir with the number one on his Red Bull for the first time.
Hamilton meanwhile has a hungry new team mate in fellow Briton George Russell, arriving from Williams and eager for a first win.
Both drivers have already warned the fans not to expect too much, with the Mercedes bouncing on the straights as downforce is gained and lost.
The team, chasing a record-extending ninth successive constructors' title, and Hamilton can never be written off, however.
"If you think that what you saw at the end of the last year was my best, wait till you see this year," Hamilton said last month.
Red Bull and Verstappen have been pleased with their car's performance while highlighting a growing threat from Ferrari, climbing back into contention after years of under-performing.
The Italian team have not won a race since 2019 or a championship since 2008 but ending at least one of those two droughts no longer looks like a distant dream.
Mercedes team boss Toto Wolff spoke for many in hoping Ferrari do step up with Charles Leclerc and Carlos Sainz.
"As a fan, I love Ferrari. They are the greatest name in Formula One and it cannot be that Ferrari is not competing for race victories and titles," said the Austrian.
"Winning championships is something different, many things have to come together to achieve that, but I think for all of us fans of the sport Ferrari needs to be in the mix. We have missed them in the last few years."
The calendar is set for a record 23 races, with Miami debuting in May as a second U.S. round but Russia cancelled as a result of the war in Ukraine and a replacement yet to be confirmed.
Russian driver Nikita Mazepin has had his contract terminated by U.S.-owned Haas, with experienced Dane Kevin Magnussen making a comeback alongside Mick Schumacher.
Thailand's Alex Albon, previously with Red Bull, is at Williams after a year away.
China is again absent from the calendar but has its first race driver in Alfa Romeo's Guanyu Zhou, the only rookie on the starting grid and team mate to Hamilton's former sidekick Valtteri Bottas.
Three sprint races are scheduled, but with points now extending to the top eight in Saturday's 100km dash.
Germany's Nico Hulkenberg will replace compatriot Sebastian Vettel in the Aston Martin team this weekend after the four times world champion tested positive for COVID-19.
The following, in 2021 championship order, looks at how the teams are shaping up (drivers given with racing numbers).
MERCEDES
44-Lewis Hamilton (Britain), 63-George Russell (Britain)
Mercedes are chasing a record-extending ninth successive constructors' title, with Hamilton seeking to push his many records (103 wins and poles) into new territory after missing his eighth crown in a controversial end to 2021. Russell joins from Williams in place of Valtteri Bottas in an all-British lineup and hoping for a first F1 win. The W13 car has had problems with downforce on the straights but history has taught rivals to be wary of Mercedes claiming to be off the pace.
Prediction: Third at the moment but cannot be ruled out.
RED BULL
1-Max Verstappen (Netherlands), 11-Sergio Perez (Mexico)
The number one replaces 33 on Verstappen's car as the Dutch youngster starts as world champion for the first time. Red Bull set the pace in testing and looked pretty pleased with their car's trouble-free performance. Perez, hoping for a contract extension beyond 2022, is now well settled in and has an important team role to play.
Prediction: Early favourites, fighting for both titles.
FERRARI
16-Charles Leclerc (Monaco), 55-Carlos Sainz (Spain)
Ferrari have not won a race since Singapore in 2019 or a title since 2008 but long-suffering fans have plenty to be excited about, with the car looking well-balanced and quick in testing and rivals pointing to them as the team to beat. Sainz is no longer a newcomer at Maranello and the partnership with Leclerc is working well.
Prediction: Race winners, top two on current form.
MCLAREN
3-Daniel Ricciardo (Australia), 4-Lando Norris (Britain)
Another settled line-up, with the experienced Ricciardo hoping for a much better season after a difficult first year at Woking despite leading a one-two at Monza. That was McLaren's first victory since 2012 and Norris will be hoping to add his name to the list of winners this year. The Mercedes-powered car is quick but was troubled by brake problems in testing while Ricciardo was sidelined by COVID-19.
Prediction: Fourth again, but looking for race wins.
ALPINE
14-Fernando Alonso (Spain), 31-Esteban Ocon (France)
Under new leadership, with principal Otmar Szafnauer moving from Aston Martin. Testing was mixed, troubled in Barcelona but with the car looking much more solid by the end in Bahrain. Double world champion Alonso, 40, is as committed as ever in a season likely to determine his future in F1 with highly-rated Australian reserve Oscar Piastri waiting in the wings.
Prediction: in danger of slipping back.
ALPHATAURI
10-Pierre Gasly (France), 22-Yuki Tsunoda (Japan)
Honda have officially departed although the engine remains the same. Gasly, a race winner, is still the leader while Tsunoda should be more consistent after his rookie year. The car looked strong in testing.
Prediction: Targeting fifth, more likely to stay sixth
ASTON MARTIN
5-Sebastian Vettel (Germany), 18-Lance Stroll (Canada)
Luxembourger Mike Krack has taken over from Szafnauer as team principal at a Mercedes-powered team going through big changes, with a new factory being built and staff expansion. Seventh was a disappointment last year and a return to the top four is the target.
Prediction: Midfield battlers
WILLIAMS
6-Nicholas Latifi (Canada), 23-Alex Albon (Thailand)
The former champions pulled themselves off the bottom last year but the Mercedes-powered team remain something of an unknown quantity. Red Bull-backed Albon returns to the grid after a year racing in the German DTM series and with plenty of hunger. Latifi is now in his third season.
Prediction: In danger of slipping back.
ALFA ROMEO
77-Valtteri Bottas (Finland), 24-Guanyu Zhou (China)
Bottas, replacing retired compatriot Kimi Raikkonen, has a leadership role to play as he starts his post-Mercedes career alongside the only rookie driver on the grid, and first Chinese to start in F1. That will guarantee plenty of interest but points will still be hard to get, with reliability a concern even if the Ferrari-powered car appears fast.
Prediction: Ahead of Williams.
HAAS
47-Mick Schumacher (Germany), 20-Kevin Magnussen (Denmark)
The only team not to score in 2021, Haas have made headlines already with the Russian invasion of Ukraine leading to a split from title sponsor Uralkali and Russian driver Nikita Mazepin. The return of Magnussen should raise morale as well as providing a benchmark for Schumacher in the German's second season. The Ferrari-engined car looks a lot better than last year's.
Prediction: Points, back in the midfield.
-Reuters