Best Moments of the Season
That 4th place finish in Singapore was a wonderful effort from Sainz and his radio message afterwards made it clear how much it meant to him. Perhaps even more impressive was his 7th place finish in Austin, his debut race for Renault. Joining a team and performing that well after just one race says a lot about his ability.
Worst Moments of the Season
There were a few moments that showed that Sainz still has more to learn. His crash in Canada could have been avoided and slamming into Stroll in Bahrain was clumsy.
Target for Next Season
If Renault continue their progress, Sainz should be able to build on his points tally from this year, he may even have an outside chance at a podium.
Points mean prizes in F1, and Sainz accumulated plenty more than he was entitled to in that Toro Rosso. Realistically, 9th place in the standings was the absolute maximum he could've got out of his season, so there's very little more you could ask of him.
I think the best certification of Sainz's success is to look at the other drivers behind the wheel of a Toro Rosso and also some of the individuals he beat. Take a look at the other three Toro Rosso drivers for the year. Gasly, Kvyat and Hartley combined for 5 points in 24 races, compared to Sainz who achieved 48 in 16 races. Drivers he beat include Hulkenberg and the Williams drivers who definitely had the machinery at hand to beat him.
Obviously there's still more to come from Sainz and he needs to improve in a few areas, but if he keeps up this form, he's going to be a threat in F1 for years to come.