Michael Schumacher showed he was far from a spent force by producing his most competitive drive since his comeback at the Spanish Grand Prix on Sunday.

The seven-times champion, making a Formula One return with Mercedes at the age of 41 and after three years out, finished fourth after keeping championship leader Jenson Button's McLaren behind him all afternoon.

Despite chalking up his highest finish since his farewell to Ferrari in Brazil in 2006, and more than doubling his meagre points tally for the season so far, the German was far from happy.

His car was clearly no match for the pace-setting Red Bull of Australian winner Mark Webber, with Schumacher finishing more than a minute behind, but he could at least start to believe that a turning point had been reached.

After the disappointment of the previous race in China, where Schumacher limped home 10th, the sport's most successful driver showed he was far more comfortable in the different chassis that Mercedes had given him.

He outqualified compatriot and team-mate Nico Rosberg for the first time this year on Saturday and passed another milestone by beating him comfortably on Sunday as well.

"It was quite an entertaining race right from the start even if we knew from the beginning that there would not be a chance for us to compete for a podium place if everything goes as normal," said Schumacher.

"Still, it was exciting for me to manage to keep the position that I gained.

"But then, I am obviously not too happy as today we could only defend. All we could do was to hope for reliability problems of others in order to make up positions and that's not really what you want to do," he added.

The Circuit de Catalunya is famed for a lack of overtaking and Sunday's race was no exception. As in the previous nine years, the driver on pole position was again the winner.

Button, who won in Australia and China, was also hampered in his efforts to get past the wily German by losing his dashboard display.

"It was an interesting fight with Jenson but all I could do is try to not give him a possibility to overtake," said Schumacher, who has won six times in the past at the track in the hills north of Barcelona.

"In the end the gap to the front is just too big to be really happy after this race.

"For Monaco, we hope that the characteristics of the track will suit our car better."

The next race, in the Mediterranean principality in seven days' time, is one that Schumacher has won five times before.