By FOX Sports Staff
Hamilton has helped Mercedes achieve considerable success over the first four races of his debut season and currently lies third in the drivers' championship.
The ex-McLaren man has also consistently outqualified Rosberg although the German did secure pole position at the Bahrain Grand Prix.
However, Rosberg could not capitalise on the front-row start and suffered tyre management problems in the race. By the end of the 57 laps, he could only finish in ninth while Hamilton pulled off a late surge to secure ten valuable points.
Berger does not agree, though, that Rosberg would be feeling the pressure of expectations and pointed towards Rosberg's track record over the past three seasons as evidence that the 27-year-old can deliver.
"That's what they said about (Rosberg alongside Michael) Schumacher," Berger told Auto Motor und Sport.
"Rosberg has proved how good he is. If he can also hold Hamilton at bay, it will be another milestone.
"For me, those two (Rosberg and Hamilton) are on the same level. Each has his own strengths.
"One has the cooler head, the other more emotion, and it's pretty even."
Moreover, Berger believes that Mercedes, as an engine supplier, always had the potential to become one of the frontrunners.
"It's not surprising," he insisted, "because they have the best engine and two great drivers."
"It was clear that at some point they would start to get the chassis right.
"Step by step they are coming to the front."
Mercedes are fourth in the constructors' championship and are doing much better than traditional heavyweights McLaren, amassing 41 more points than the Woking outfit.