Done deal on title but Hamilton won't ease off in Brazil

Two races to go in the F1 season, you could forgive the drivers and the teams for feeling it's like the end of a school term - a bit of a breeze. After all, the drivers and team championships have been decided and Mercedes have nothing left to prove.

The thing is, it doesn't work that way in this sport. An F1 driver is a competitive beast, and none more so than world champion Lewis Hamilton. He won his third title in the United States, and on the evidence of the race in Mexico, he has no intention of easing off and giving anyone any slack, least of all his beleaguered teammate Nico Rosberg.

Rosberg, of course, is in a battle to take second place in the standings. He's 21 points ahead of Ferrari's Sebastian Vettel. Given the dominance of the Mercedes engine this year he should be a country mile ahead.

Still, the German has taken pole for the last four races, and in Mexico managed to convert that into a win. But it was no thanks to Hamilton. He'd made it clear he wasn't in the business of helping his teammate now he'd secured the title. The radio row over pitting during the last race underlined that. He felt the team wanted to please Rosberg and pulled him in for fresh tyres when he could have won.

The Briton is a serial winner, increasingly mature and able to play a nuanced mind game. There will be no easing off in Brazil this weekend. Race wins, pole positions are all precious things, records are there for the taking. We have seen enough team orders over previous years to welcome Hamilton's resolve.

We should also praise the Mercedes team for their handling of the pair, whose relationship has been fractious at best over the last 18 months. Despite the obvious frustration of Rosberg, they know he could also be on the verge of greatness. He has also matured, and while things have not gone his way recently, if the team continue to handle him carefully he may still be a world champion in the not-too-distant future.

It's also good that no one is taking it easy at the end of the season because the Interlagos track in Sao Paulo is one of the best you'll ever see. It may not be the newest, or best appointed, but it is exciting. Just cast your mind back to Hamilton's first world championship, won on the final corner in 2008.

No end-of-term slacking from the drivers in Brazil then, but for one aspiring F1 contender, a definite end of an era. Williams test driver Susie Wolff is retiring from the sport. The 32-year-old believes her dream of getting onto the grid to race "isn't going to happen".

It's a real shame, but another example of how tough this sport is. She must have known the writing was on the wall when the team decided she wouldn't be used in the event of Valtteri Bottas being injured for Malaysia. She was the most senior backup driver, but Williams would have looked elsewhere.

Once you get a vote of no-confidence, it must be hard to carry on. It's disappointing there won't be a woman on the F1 grid, but don't expect her to disappear. She is, after all, married to Mercedes boss Toto Wolff. It would be nice to see another woman in an influential position, even if in management and not on the grid.