Well that was entirely unexpected.
Let's deconstruct it a little bit. In hindsight, two things are clear to me. First, the Mercedes is not as kind to its tires as the Ferrari is. Second, Mercedes made two strategy mistakes, in not holding back enough option tires for Sunday, and in making the pit stop under safety car in the first place.
If we game this out a bit, then what would have happened is that after the safety car the Mercedes cars would have led, then pitted for prime tires. Vettel would have made his only stop under green and come out behind the Mercedes. Then when the Mercedes cars pitted again, they would be much closer together. The Mercedes would be a faster car on fresher tires, but with the Ferrari handling its tires much more gently it might have been more interesting in the closing stages. If Hamilton was truly unhappy with his car, he might have been persuaded by Vettel to make a mistake. But I think that unlikely, I think Vettel would be more content to not risk his second place.
Mercedes' strategy mistake of not holding back another set of options is probably a direct result of the car being harder on its tires.
But all of this is affected in unpredictable ways because of the heat on Sunday. Did the Mercedes suffer? Hamilton's comments suggest that maybe they did. They seemed to struggle a bit, while both Ferrari cars ran with good pace throughout the race.
Due to the heat I don't think we can call this solid competition yet, or even a championship horse race. Lets wait and see how things play out in China, or better yet once the series returns to Europe.
But for now, I'll take it.