#3 Third time when teammate to the champion did not win a race:

Bottas could probably be called the greatest supporting driver ever (we did not think that title could have been taken by anyone other than Rubens Barrichello, but here we are!). His poor weekend at Abu Dhabi again condemned him to a record which he would not prefer to be a part of- he became the third driver to not win a race in the same season when his teammate was the champion.
The first two on that list are Rubens Barrichello, who went win-less in 2001 when teammate Schumacher won the second of his five titles with Ferrari; and Mark Webber, who failed to win a single race in 2013, when teammate Sebastian Vettel won his fourth consecutive world title with Red Bull.
In conclusion, it can be said that after an inauspicious start at Australia, Bottas actually pulled up his socks to deliver good qualifying and race performances but luck just did not favour him then. Post the mid-season break though, he himself tapered off and could not replicate his early season form..
He looked set to take third place in the drivers' championship but a run of four consecutive fifth-place finishes towards the end of the season ensured that he finished fifth in the championship. He'll be looking to put this season behind him and start afresh in 2019, possibly even launching a title bid to stay at Mercedes beyond next season.