Briefs 2-Portugal's Petit to quit internationals after Euro 2008

May 22 (Reuters) - Sports news in brief from around the world:

Soccer - Benfica's 31-year-old midfielder Armando Petit plans to retire from internationals after Euro 2008, having played at two World Cups and Euro 2004.

"This is probaly my last European (championship) and I will say goodbye to the Portugal team," Petit, who has 53 caps, told reporters at a training camp in Viseu, 300 km from Lisbon.

Euro 2008 runs from June 7-29 in Austria and Switzerland.

Soccer - Sampdoria have extended coach Walter Mazzarri's contract by a year to 2010 after he led them to a sixth-place finish in Serie A and UEFA Cup qualification.

"I'm happy and I thank the club, the president and the fans. I will work with enthusiasm to take these colours even higher," Mazzarri told a news conference.

Motor racing - Former Minardi Formula One driver Robert Doornbos will drive the AC Milan car in the Superleague Formula single-seater series which starts in August with teams racing in the colours of selected soccer clubs, organisers said.

"I've always been a huge AC Milan fan," said Dutchman Doornbos, whose aunt Jeanine was physio to Netherlands soccer players Marco van Basten, Franck Rijkaard and Ruud Gullit when the trio played for the Italian Serie A side.

Motor racing - Monaco's Stephane Ortelli will not take part in next month's Le Mans 24 Hours race because he is not fully fit following an ankle injury, his Oreca team said.

Ortelli, a Le Mans winner 10 years ago, crashed in last month's 1,000 km of Monza and has just started rehabilitation. He will be replaced by France's Simon Pagenaud.

Golf - Fijian Vijay Singh, who pulled out of the PGA Championship at Wentworth on Thursday with a rib injury, hopes his place at next month's U.S. Open is not in jeopardy.

"I'm going to go home and rest. Maybe go to the doctors to see if I can get an MRI (scan) done," said the world number nine. "I have to get myself sorted out as the U.S. Open is only three or four weeks away."

(Editing by Ken Ferris)