Mercedes boss Toto Wolff believes rival Ferrari lost important "momentum" in Formula 1 with its defeat in Bahrain after Charles Leclerc suffered late-race heartache with an engine problem.
Ferrari came into the 2019 season as the favourite after showing strong pace in winter testing, but it has yet to win a race in 2019.
After a set-up error in Australia, Ferrari looked set to win with Leclerc in Bahrain. But with 10 laps to go, Leclerc suffered a short circuit within his injection system control unit and Lewis Hamilton took the victory.
Ferrari has since been searching for more performance with its car and has been experimenting with sacrificing some of its top speed for greater downforce, and Leclerc had a breakthrough with pole position in Austria before losing out to Max Verstappen in the race.
Reflecting on the dominance of Mercedes, winning every race of 2019 until Verstappen's Austria win, Wolff believes Ferrari's Bahrain defeat was costly.
"I think somehow the momentum that Ferrari had in Bahrain was lost because they had the quickest car and they should have won the race with Leclerc," Wolff told Autosport in an exclusive interview.
"Charles was the quickest guy in Baku, before his crash in qualifying, and Sebastian was in the lead in Montreal before the penalty came. So it could easily have been very different based on pure performance."
Wolff insists that pre-season concerns over Ferrari's form were genuine.
Mercedes endured a challenging first test before concerns grew when the updated W10 did not work as expected.
"I was worried," Wolff admitted. "I wasn't worried about the first test, because in the first test we saw a very impressive Ferrari.
"When you stood out [by the] track, you could see the braking into Turn 1, and Turns 2 and 3. They were mighty.
"You could see on the track that the Ferrari was really good, but then I knew that we would bring an upgrade package that would completely change the car.
"And we put it on the track on the Monday and it didn't correlate, and on the second day, it didn't correlate.
"We thought we had a real problem there. But it all changed on the third day when the car somehow came together.
"And on the fourth day when we were equalling Ferrari's time, it was the first time in the eight days of testing we had the feeling that there is a path that seems sensible."