Red Bull boss Christian Horner has said that Sebastian Vettel will get even better in his career as the years progress.

The 25-year-old won the world championship on Sunday for the third year in a row.

"He has had a remarkably impressive career so far," BBC Sport quotes Horner as saying. "As a driver, he will continue to get better and I think we have yet to see the best of him."

Horner, though, believes that Vettel will face stiff competition to retain his world championship title next season.

"I think both Fernando [Alonso] and Lewis [Hamilton] and Jenson [Button] are potentially very strong threats for next year," he said.

"Fernando has driven with a great tenacity and consistency this year. He is at his peak. He will be a formidable competitor next year."

Vettel joined Red Bull in 2009.