Sebastian Vettel says it is unfair to compare his results this year with team-mate Daniel Ricciardo due to reliability issues.

Ricciardo has two victories this season and three further podium finishes, while Vettel has just two podiums to his name this year. However, the qualifying head-to-head is similarly striking as Ricciardo leads Vettel 6-3. When asked about the qualifying record between himself and Ricciardo, Vettel replied: "First of all, I won't argue that he is doing a good job.

"On my side, I think I have plenty of qualifying sessions where we had some sort of trouble. I don't remember all of them, in terms of what the nature was, but we lost out many times because of that and in the races as well. At some times it was obviously getting quite frustrating, but Formula One can be very nice and it can be very brutal as well by not giving you the chance to show what you can do.

"I'm not interested in comparing too much, because on my side it's not fair to compare. Daniel has had a smoother year - I'm not saying perfect year because he's also had some issues - but way less than I had, so it's not entirely fair to compare. That's why I won't argue with that, he did a great job so far."

And Vettel said he is primed for more issues with his grid positions in the second half of the season as penalties for power unit component usage start to kick in.

"I hope we have no issues with reliability. It's clear that the second half won't be smooth for us because we have to pay the price of the first half in terms of use of engine and other components. We have to change them at some stage and obviously we will receive the penalties for that. It's not great from a driver's perspective, but it's part of the rules and part of the game.

"Other than that, we have already made big progress. If you look at the start of the season I was really fighting with the car and the last couple of races were very good. We didn't get it to come together, but I'm sure at some stage we will turn it around and we will be in a happier place."