The only run came when Daniel Bard (0-2) walked Evan Longoria on four pitches with the bases loaded in the seventh.

Shields (2-0) led the majors with 11 complete games last year and had a chance for another until he walked Dustin Pedroia with one out in the ninth. Fernando Rodney retired the next two batters for his fourth save in four chances.

Shields gave up four singles and two walks while striking out five as the Rays finally shut down the team that had outscored them 31-12 in the previous three games. Only one Boston runner got past first base.

The loss was Bobby Valentine’s first at Fenway Park as Boston’s manager. Fans booed when he went back to the dugout after lifting Bard for Justin Thomas following the run-scoring walk.

During an interview aired on WHDH-TV Sunday night, Valentine questioned Kevin Youkilis’ commitment to the game. He apologized to his third baseman on Monday. Valentine had said he didn’t think Youkilis was “as physically or emotionally into the game.”

Joe Maddon got his 500th win as a manager, all with Tampa Bay, as the Rays stopped a four-game losing streak.

The traditional Patriots’ Day home game began at 11:04 a.m. The holiday observed in Massachusetts and Maine marks Paul Revere’s ride and the battles of Lexington and Concord in 1775.

Shields retired the first four batters before Cody Ross’ broken-bat single off the pitcher’s glove. The next six Red Sox made outs before Adrian Gonzalez singled to left. He was erased on a double-play grounder in the fourth.

Shields walked Nick Punto with two outs in the fifth, allowed singles to Dustin Pedroia in the sixth and Ross in the seventh and walked Pedroia in the ninth. Pedroia took second on a groundout, David Ortiz was walked intentionally and Ross took a called third strike, slamming down his helmet after the final out.

Bard gave up three hits through six innings and set down the first two batters in the seventh. Then he lost his control.

Sean Rodriguez walked, Desmond Jennings singled and Carlos Pena walked, loading the bases. Pitching coach Bob McClure visited Bard and left him in the game. The move backfired as Bard walked Longoria with his 111th pitch. That’s when Valentine went to the mound to lift Bard and was booed on the walk back.

Thomas ended the threat by retiring Luke Scott on a fly to right.

Notes: Republican presidential candidate Mitt Romney attended the game. He chatted with New England Patriots owner Robert Kraft … Youkilis sat out the game with a minor groin injury. … In 1968, the Red Sox began the tradition of playing a single game with a morning start on Patriots’ Day. The Rays are 3-0 in those games. … Ryan Sweeney was 0 for 3 after hitting safely in the other seven games he played for Boston.