Mercedes boss Toto Wolff believes Ferrari have only shown glimpses of the threat they pose to his team at 2016's opening two races.
Despite Ferrari clearly appearing to have closed the pace gap on F1's world champions over the winter, Mercedes have made their strongest start to a season and dropped only three points from a maximum 86 across the first two rounds.
By contrast, Ferrari already tail by 50 points in the Constructors' Championship with their early-season total compromised by two reliability failures.
But Wolff has warned Mercedes to keep on their toes ahead of this weekend's Chinese GP.
Asked in a Q&A on Mercedes' YouTube channel to assess the team's start to 2016, Wolff replied: "Very good. Two races in, one-two and one-three - it doesn't go much better [than that].
"We haven't seen the best out of Ferrari yet. They are struggling with reliability. We have seen glimpses of pace, they have definitely caught up and it's more difficult for us.
"But, definitely, with our results I am happy."
When is the Chinese GP on Sky?
Ferrari's points deficit after two races is their largest at this stage of the season since F1's current points format was introduced in 2010 and Mercedes have now won the last eight races - their joint-best run yet.
But the Scuderia have taken heart from reducing the gap to the front and the fact Kimi Raikkonen finished just six seconds behind race winner Nico Rosberg in Bahrain.
"We are nearly there in qualifying," Arrivabene told Sky Sports F1.
"There's a long way to go, so we need to work hard and be concentrated on our performance on the race."
The Shanghai International Circuit plays host to this week's third round of the campaign, with the circuit one of the hardest on the calendar for front-tyre wear.
Mercedes, winners of the race in three of the last four years, have selected fewer sets of Pirelli's quickest tyre, the supersoft, than Ferrari with Lewis Hamilton having one more set of mediums, and Rosberg one more set of softs, respectively than the Scuderia's drivers.
Don't miss the F1 Report: Chinese GP preview on Wednesday at 8.30pm on Sky Sports F1. Five-time GP winner John Watson and F1 historian Roger Smith join Natalie Pinkham to look ahead to round three of the season.