A season that started in such a promising manner, only for the reliability bug to bite. And boy, did it bite hard. Attempting to compete with Mercedes and Ferrari is hard enough as it is with a serious engine deficit. Throw unreliability into the mix and it becomes almost impossible.
The wins that Ricciardo forged in China and Monaco will be fondly remembered for many years to come but they were the only two occasions he found himself on the podium. As previously mentioned, reliability played a huge part in this but to suggest that was the only factor at play would be false. Teammate Max Verstappen regularly outperformed the Aussie, particularly on Saturdays.
Midway through the season it was shockingly announced that Ricciardo would leave Red Bull for Renault in 2019. The reason why is still relatively unclear (A new challenge? Worried about Honda's arrival? Preferential treatment for Max?) but giving up a top car is a bold move. Will it backfire? Only time will tell.