Nico Rosberg will offer a stronger challenge to Lewis Hamilton in the race for the 2015 Formula 1 world championship, according to David Coulthard.
The German was beaten to the 2014 drivers' title after his teammate won the season-ending Abu Dhabi Grand Prix in November, but Coulthard is confident that Rosberg has room for improvement in the upcoming campaign.
Speaking at the Autosport Motor Show, the Scot said: "I see Nico being stronger than he was as he now has this experience of battling for a World Championship. That was the first time he had the spotlight of expectation.
"A lot of drivers, and I know this from personal experience, think, 'if I was in a winning car then winning would be easy', but winning is not easy, even in a winning car.
"It's difficult, and it should be difficult, as usually you have a strong competitor in the other car."
The 2015 season gets underway in Melbourne on March 15.
