Sebastian Vettel and Lewis Hamilton traded victories in Melbourne and China, but it was Vettel's win last weekend in Bahrain that has Mercedes worried, Lauda admits.
"The alarm bells are ringing with us," he told Osterreich newspaper.
"Those who win in Bahrain have a certain buffer for the next three races," Lauda added.
Indeed, both Hamilton and his Mercedes teammate Valtteri Bottas admitted in Bahrain that the main problem with the 2017 car is the new Pirelli tyres, particularly in hotter weather.
But others think Ferrari has simply given quadruple world champion Vettel a tantalising sniff at a fifth title.
"The Vettel factor can decide the world championship this year," Vettel's first F1 boss Gerhard Berger told Sport Bild.
The former F1 driver admitted he is surprised with Ferrari's pace so far in 2017.
"I would have lost every bet before the season," Berger smiled, "because I doubted that Ferrari would really beat Mercedes."
Another of Vettel's former chiefs, Dr Helmut Marko, agrees: "Sebastian is at one with his car.
"He is constantly on the limit, not making the smallest mistake and always knowing what to do. This is pure driving pleasure for him.
"Like this, Vettel is very hard to beat -- especially when Mercedes is making mistakes," the Red Bull official added.
Finally, an unnamed current F1 driver also tipped Vettel to emerge with spoils at the end of a long head-to-head with Mercedes' Hamilton in 2017.
"Hamilton lacks the bite," he said. "You can only rely on talent alone when you have a car that is a second faster. Three tenths per lap is not enough to beat a Vettel."