Rubens Barrichello believes the battle for the F1 2012 drivers' title will come down to a two-way scrap between Fernando Alonso and Sebastian Vettel.

Alonso currently leads the drivers' championship by 40 points, and while Mark Webber is his closest rival, Vettel is only two points further back, and five up on Lewis Hamilton, who lies fourth. Kimi Raikkonen is then fifth, one point behind Hamilton.

Despite that though, Barrichello believes Vettel will mount the best challenge in the second half of the season, which gets underway at the end of this month, when the circus reconvenes at Spa-Francorchamps, for the Belgian Grand Prix.

"Alonso is in the form of his life," Barrichello said in an interview with German publication, Auto Motor und Sport this week.

"He's not in the fastest car, but he makes the most of it and now his pursuers take points off each other.

"In the end it will result in a duel with Alonso and Vettel."

As for his old rival and Ferrari team-mate, Michael Schumacher, Barrichello added that it was always going to be difficult for the multiple-world champion to return, although Raikkonen hasn't had so many issues.

Indeed while Schumacher took more than 40 races to get back on the podium, Kimi did it in just four...

"I like the way he [Schumacher] has decided to approach the matter [as he nears his 300th F1 race] and I knew that it would be difficult after a three year break to immediately regain a foothold.

"It has really surprised me then how Kimi has had fewer problems with it," Barrichello remarked.