Mercedes chief Toto Wolff is well aware of the challenge his team have on their hands to retain their Formula One title as the new season gets under way in Melbourne.
Star driver Lewis Hamilton won the drivers' championship in 2018, while the Silver Arrows cruised to the constructors' title.
However, this weekend's Australian Grand Prix follows hot on the heels of testing in Barcelona where Ferrari were consistently faster than Mercedes.
Sebastian Vettel and the Scuderia will be looking to end Hamilton's dominance this season and, while insisting Mercedes did not have it easy last term, Wolff recognises their threat.
"Last year, we had to give it absolutely everything to come out on top," he said. "From what we have learned so far, this year will be even tougher.
"It will push us to our limits - and that's an exciting prospect for every single one of us. Judging from the performance in Barcelona, it looks like we will have a proper fight on our hands in Melbourne.
"But an F1 season is not just about who comes out of the blocks quickest.
"Under new regulations like we have this year, it is about who is able to adapt best to the new rules and the new tyres and all the challenges that we will have to master during the year."
TALK OF THE PADDOCK
In the first race of a new season, there will be plenty of attention on those drivers who have switched teams since last year.
Charles Leclerc is in at Ferrari, with Pierre Gasly promoted to Red Bull, while Kimi Raikkonen is back with Alfa Romeo - formerly Sauber.
Perhaps most notable of all, though, is Daniel Ricciardo's arrival at Renault as the team seemingly look to challenge the big three this season.
Such a bid certainly appeared to be on boss Cyril Abiteboul's mind this week as he claimed: "Our driver line-up of Daniel and Nico [Hulkenberg] is perhaps the strongest on the grid."
At Ricciardo's home race, a fast start would represent a fine way to back up such a statement.
RACEWEEK SCHEDULE (all times local)
No Australian driver has ever earned pole position, reached the podium or won at their home grand prix in F1.
2018: Sebastian Vettel
2017: Sebastian Vettel
2016: Nico Rosberg
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