Whilst professing himself pleased with his own performance for his first time in a grand prix in more than four years when he replaced Sakon Yamamoto in Singapore a week-and-a-half ago, F1 returnee Christian Klien has conceded that he was 'disappointed' by the Hispania Racing F110.

Drafted in almost literally at the eleventh-hour to substitute regular driver Sakon Yamamoto - who had been struck down with food-poisoning - Klien belied his lengthy period away from the grid in the top flight by going on to impressively and comfortably outpace team-mate Bruno Senna in both qualifying and the race, despite the young Brazilian rookie having been in the car for virtually the whole season.

A hydraulics problem ultimately curtailed the Austrian's race at half-distance, but the 27-year-old insisted he was satisfied with his own form - if rather more underwhelmed by the unexpected limitations of the equipment at his disposal.

"I used this chance pretty well for my first time in the car for the whole weekend," Klien told F1pulse. "I had quite a good performance, although I had to get used to the car and set-up again. From Friday, I proceeded step-by-step and got more-and-more comfortable in the car. Finally, qualifying went very well - I proved that I was quick and made the most out of it.

"[In the grand prix] I pulled a gap of eight seconds from Senna, and I was really, really happy with the performance compared to my team-mate, but it was a pretty tough race, because the car was very difficult to drive around that track - we missed a lot of downforce. We were even far away from Lotus and Virgin. It was more-or-less [enough] to keep the car on the track. That was a bit disappointing, actually."

Whilst it has now been confirmed that Klien will cede the cockpit of the #20 HRT machine back to Yamamoto for this weekend's Japanese Grand Prix at Suzuka, the former Red Bull Racing and Jaguar ace confesses that he hopes his Singapore showing might have been enough to earn him another chance over the final three outings - and that perhaps he may even have eased open a few doors for 2011.

"Later on, I don't know," he mused. "Obviously, the performance [in Singapore] was pretty good. Maybe the team will make another decision towards the end of the season, but I have no idea at the moment. We are checking the possibility with teams who have a seat left for next year. The whole weekend in the car helped to show [my performance] to get a better chance for next year to get a drive."