Sebastian Vettel

Vettel pictured winning the 2017 Australian Grand Prix
Last season was a difficult one for the four-time World Champion. However, the off-season seems to have re-invigorated him. He has qualified on the front row both times so far this season, and managed the tyres extremely well in Australia which helped him to the race victory as Hamilton struggled to manage them. He was denied a chance of victory in China after Giovinazzi's crash brought out the safety car, which enabled Hamilton to re-emerge ahead of Vettel after he had pitted under the Virtual Safety Car. He ended up finishing just six seconds behind Hamilton who went on to win the race. The Ferrari looks really quick this season and extremely capable of challenging Mercedes. Also, his overtake in China on Daniel Ricciardo was a highlight of the season so far. The battle many have been waiting for could be arriving - that between Lewis Hamilton and Sebastian Vettel for the World Championship crown, and on the basis of the first two races it looks like it will be extremely close between them. His talent has never been doubted, but it seems like he is much calmer in the car and his talent is being displayed once again.
Carlos Sainz

Towards the end of the last season, Sainz picked up a couple of impressive sixth placed finishes - and he impressed last year in a car which was down on engine power after using a year-old Ferrari engine.
It seems like he has carried on from where he left off last season, with two solid points finishes. Also, it must be noted his bravery in the Chinese Grand Prix, when he decided to start on the super-soft tyres when everyone decided to start on intermediates on a clearly still damp track. Yes, he spun off at turn 1 and brushed the wall, but from then on drove a stellar drive into 7th place, and for a while was running close to the Mercedes, Ferraris and Red Bulls, and was the only driver other than the Mercedes, Ferrari and Red Bull pair to finish on the lead lap, and also the fact that he ran above Bottas for a substantial chunk of the race is encouraging.
If Ferrari decide not to renew Raikkonen's contract for 2018, and don;t be surprised as he will be 38 years old, and it is possible will look for new blood, Sainz is definitely a driver that Ferrari should consider, especially on the evidence of this season so far.
Fernando Alonso

In testing the McLaren car seemed to encounter all sorts of problems and desperately struggled for any meaningful running. It looked like the team would struggle at the back of the grid, and would be engaged in a battle with Sauber.
Yet Alonso has defied many people's thoughts by running in the points in the first two races. OK, he failed to finish both, but that was through no fault of his own after technical issues. He makes that McLaren look a bit decent when in reality it is easily one of the worst cars on the current grid. Alonso deserves a much better for the talent he has, and should possibly look to move on from McLaren for next season, in order to be able to fight at the top.
Other notable mentions: Esteban Ocon who has been very solid so far for Force India, and Max Verstappen - particularly his surge up the grid in China and his damp-weather display.