It took a monster deal to lure cornerback Nate Clements to Monster Park, but on the opening day of the NFL free-agent period, the San Francisco 49ers delivered, agreeing with the most coveted player in the market on a landmark contract.

The 49ers rewarded Clements, the top player in the ESPN.com ratings of the league's unrestricted free agents, with an eight-year, $80 million contract that includes $22 million in guarantees.

By virtually any standard used to assess NFL contracts by those in the industry, the pact makes Clements the highest-paid defensive player in league history.

"This is Year Seven for me, and I've never even had a taste of the playoffs," Clements told the Associated Press. "The 49ers "not only showed the most interest, but I felt that they were moving in the right direction."

Later in the day, San Francisco officials continued reshaping their secondary, as the team reached agreement with former Philadelphia Eagles starting strong safety Michael Lewis. The details of Lewis' contract were not yet available.

The blockbuster deal of the day, though, belonged to Clements and agent Todd France, as anticipated. A year ago, when Clements signed a one-year contract in Buffalo as the team's franchise player, France negotiated into that deal the stipulation that the Bills could not use the franchise designation on his client for a second year in a row.

So for the past year, NFL teams in need of a premier cornerback knew Clements would be available, assuming he did not sign an extension in Buffalo. And while there were plenty of potential suitors, like Cleveland and Tennessee, it turned out that Clements needed to visit just the 49ers on the first day of free agency to find a new home and record payday.

Clements, 27, is in the prime of his career and, playing a premium position, he was poised for a huge contract.

The former Ohio State star, a first-round choice of the Bills in the 2001 draft, is a physical cornerback who combines size, speed and raw coverage skills. In his six years with the Bills, he never missed a game, appearing in 96 straight. He registered 432 tackles, 23 interceptions, 61 passes defensed, 1½ sacks, 13 forced fumbles and four recoveries.

The 13 forced fumbles, a remarkable number for a cornerback in a six-year span, are reflective of Clements' physical nature.

Lewis, 26, was a second-round choice of the Eagles in the 2002 draft and started as a rookie. But the five-year veteran, a former Colorado star, fell out of favor in 2006 and lost his starting job early in the season.

In 76 games, he has 318 tackles, six sacks, nine interceptions, 31 passes defensed and 10 forced fumbles. Lewis can be a liability at times in coverage, but the 49ers' coaches likely will play him close to the line of scrimmage, where he is most effective.

Len Pasquarelli is a senior writer for ESPN.com. Information from The Associated Press was used in this report.