Formula One has witnessed many great rivalries over the years. But could this season’s championship battle between Lewis Hamilton and Sebastian Vettel turn out to be the best the sport has seen yet?

The tussle between the Briton and the German – who head into this weekend’s Azerbaijan Grand Prix through the streets of Baku 12 points apart with Vettel leading – has so far been akin more to a ‘bromance’ than a full-blown rivalry.

It has certainly lacked the ferocity of a Senna vs. Prost, the bitterness of a Mansell vs. Piquet, the drama of a Hunt vs. Lauda or even the tension of a Hamilton vs. Rosberg.

But after three years of Mercedes dominance and four years of Red Bull supremacy before then, that may simply be down to the sport — and its two title protagonists — revelling in the welcome change of narrative. Come the business end of the season, with the title at stake, the love-in between the pair, their mutual admiration, could all vanish in a fit of red rage.

And when it does, it promises to be one to watch.

For of all the rivalries that have been fought over the years in Formula One none have been fought between drivers more accomplished, at least on paper, than Hamilton and Vettel. Never in the 68 year-history of the sport have a triple title winner and four-times champion gone head to head for the Formula One championship.

“The scenario I’m in right now, I’m up fighting against a four-time world champion who is at his best and he is phenomenally quick,” said Hamilton after winning the second race of the season in China to draw level on points with Vettel. “The ultimate fighter always wants to go up against the best… because then when you come out on top, it’s just so much more satisfying.”

Hamilton and Vettel’s presence in the pantheon of greats is beyond doubt. But where they ultimately stand among them will always be open to debate. By extension so will where their rivalry ranks compared to the sport’s other great battles. Could their rivalry, for instance, be better than the 1990 championship feud between Senna and Prost, when the gloves come off, simply because the Brazilian had at the time won only one title while his French rival had won three?

Raw statistics can never tell the full story. Hamilton vs. Vettel is still only just developing. The gloves are still on. Equally, nostalgia lends the past a rosy tint. Just as the question of who the sport’s greatest ever driver is can never be answered, so will the question of which ranks as its greatest rivalry be subject to debate. The best that can be done with drivers or rivalries is to place them in the context of their time.

Both Hamilton and Vettel made their debuts in 2007, the former at the season opener in Australia, the German midway through at the U.S. Grand Prix.

Hamilton was the first of the pair to win the title. That was in 2008. Since then either Vettel or Hamilton have won the title in all but two seasons, with Jenson Button scoring a fairytale triumph in 2009 and Nico Rosberg winning the championship last year.

And while this season is the first time they’ve gone up against each other, Vettel and Hamilton have been in close-fought championship battles before.

In 2012 Vettel battled all year for the title with his Ferrari predecessor Fernando Alonso, still regarded as the greatest driver of this generation but sadly marking time in an uncompetitive McLaren Honda.

The battle went down to the season finale. But the playing field was far from even, with Alonso driving a clearly inferior Ferrari and Vettel and Red Bull hitting a purple patch of form to dominate the final third of the season.

Similarly, in 2007, Hamilton and Alonso were team-mates at McLaren, driving exactly the same car fighting on exactly the same terms.

But Hamilton was in his first season in Formula One. Even though his string of podiums and victories belied his inexperience, he was still very much a rookie. Alonso too, while being the reigning double world champion, was not yet at his best.

As riveting as those battles were, the difference between them and the Hamilton-Vettel duel this year is obvious.

In the Spanish Grand Prix, for instance, there was absolutely nothing between Hamilton and Vettel as they put on a devastating display of speed and ability.

It was the first and — due to the way races have played out — the only time they have battled head-to-head for victory so far this season, and each drove the other on, tapping into reserves of ability and performance accessible only to the greats.

At the last race in Canada, after their initial laps in the final phase of qualifying the pair were separated by just 0.004 seconds. It was only when Hamilton pulled out an exceptionally blistering pole lap that the gap widened.

“He’s proven to be one of the quickest drivers on the grid,” Vettel said of Hamilton after his win in the season-opening race in Australia. “I would love to have a close battle.”

Vettel’s wish has come true, as has the wish of all of Formula One and its fans. If only Alonso could join them.

We may not have seen the full extent of Hamilton vs Vettel yet and only time will tell whether it goes down as Formula One’s greatest-ever rivalry. But it has already got the makings of a classic.