Sunday at Valencia finally vindicated his decision to sign rookie Kamui Kobayashi, according to team boss Peter Sauber.

The Japanese impressed with his feisty debut drives at the end of last year, when Toyota was on the way out of formula one and Timo Glock was recovering from injury.

On the strength of those brilliant flashes, Sauber signed the 23-year-old to complement the veteran Pedro de la Rosa for 2010; the Swiss team's first season in the wake of BMW's departure as owner.

Kobayashi's Valencia weekend did not get off to a great start when he was out-qualified by de la Rosa, but his name featured prominently throughout the race.

He leapt towards the front because he started on the harder tyres and didn't pit with the bulk of the field, but when he was running prominently his laptimes were fully competitive and he comfortably held off the reigning world champion Jenson Button.

He made his mandatory pitstop with only four laps to run, famously overtaking first Fernando Alonso and then Sebastien Buemi within sight of the chequered flag.

"Kamui was absolutely amazing," said founder Sauber before leaving Spain.

"The lap times which he put in while he was in third were stunning."

And Sauber added on Wednesday: "Signing a rookie is always something of a risk; on Sunday Kamui delivered confirmation that we made the right decision."

Signing Kobayashi was 'right decision' - Sauber