WASHINGTON — Roger Clemens’s most meaningful denial of drug use so far was also the most well-guarded.

The star pitcher gave a sworn deposition for about five hours to congressional lawyers behind closed doors yesterday, addressing his former personal trainer’s allegations. And this time, Clemens was under oath.

“I just want to thank the committee, the staff that I just met with. They were very courteous,” the seven-time Cy Young Award winner said, wearing a pinstriped gray suit instead of a pinstriped Yankees uniform. “It was great to be able to tell them what I’ve been saying all along — that I’ve never used steroids or growth hormone.” Yesterday’s deposition was the first time the seven-time Cy Young Award winner faced legal risk if he were to make false statements. Home run king Barry Bonds, another player linked to steroid use, was indicted in November on charges of perjury and obstruction of justice for telling a grand jury in 2003 that he didn’t knowingly take performance-enhancing drugs.

In the 1 1/2 months since former Senate majority leader George Mitchell released his report on drug use in baseball, Clemens strongly and repeatedly denied what his former personal trainer, Brian McNamee, said — in statements by his lawyers, in a written statement, in a video statement, during a taped TV interview, and in a live news conference.

Clemens spoke yesterday with staffers from the same House panel that — after the Mitchell Report came out — asked the Justice Department to look into whether 2002 AL MVP Miguel Tejada lied when he told committee investigators in 2005 that he never took performance enhancers and had no knowledge of other players using or talking about steroids. The FBI’s field office in Washington is handling that inquiry.

“Roger hasn’t declined to answer a single question since this matter began, and he was completely forthcoming,” one of Clemens’s lawyers, Lanny Breuer, told the Associated Press.