By Ian Simpson

WASHINGTON (Reuters) - Former baseball star Roger Clemens wove a web of deceit to cover up his steroid use, going so far as to lie about it in testimony before Congress, a prosecutor said at the start of ex-pitcher's second perjury trial on Monday.

Proof of Clemens' steroid use includes needles and bloody swabs that independent tests have shown contain the former elite pitcher's DNA and performance-enhancing drugs, Assistant U.S. Attorney Steven Durham said.

Clemens, who won the Cy Young Award a record seven times as his league's best pitcher, lied to a congressional committee in 2008 when he swore to tell it the truth about his use of steroids, Durham said in his hour-long opening statement.

"He raised his right hand, his pitching hand, the hand that won this man 354 games, millions of dollars and great fame as a major league baseball player. And at that point he took an oath to tell the truth," he told the jury.

Clemens' attempts to cover up steroid use mean "you become trapped in a tangled web of your own making, and that is the story of the defendant in this case."

Clemens, 49, is facing a second trial on charges of lying to the House of Representatives Committee on Oversight and Government Reform about whether he used performance-enhancing drugs.


Clemens, who was one of baseball's top pitchers during his 24-year career, said at that hearing he had not used steroids. He was indicted in 2010 for perjury and obstruction.

Clemens first went on trial last July. U.S. District Judge Reggie Walton declared a mistrial because prosecutors showed jurors a video clip that included material the judge had banned from the case unless it was raised by Clemens' defense team.

Clemens' defense lawyers are scheduled to make their opening arguments on Tuesday morning. The two sides agreed on Monday on a jury of six men and 10 women, with 12 to be chosen to decide the case.

The trial may run as long as six weeks. If convicted, he faces a maximum prison term of 30 years, though under federal sentencing guidelines he would most likely get 15 to 21 months.

During Durham's opening statement, Clemens, dressed in a dark suit, sat back in his chair with a hand at his chin. He made no public statements in the courtroom.

Prosecutors had hoped to tie Clemens to the same supplier of banned substances that Pettitte used -- Clemens' former trainer Brian McNamee. Defense attorneys have branded McNamee a liar.

Durham said that McNamee had injected Clemens with anabolic steroids in 1998, 2000 and 2001 and with human growth hormone in 2000.

Clemens, known as "The Rocket" during his prime, played for Boston, Toronto, Houston and the New York Yankees. He last pitched in 2007.

His is one of the biggest names linked to steroid use in baseball. Other stars who have faced questions about doping include sluggers Mark McGwire, Jason Giambi and home-run king Barry Bonds.

(Reporting by Ian Simpson; Editing by Jackie Frank, Bill Trott and Lisa Shumaker)