The national holiday of Memorial Day turned out to be a full day off for the Yankees’ bullpen as well Monday. The relievers have Bartolo Colon to thank for that with an old-fashioned complete game shutout, the ninth of his career but the first in five seasons, in a 5-0 dusting of the Athletics.

Except for the date on his birth certificate, there doesn’t appear anything old about Colon, who turned 38 last week but has turned back the clock for the Yankees this year. Still wounded by a no-decision May 18 at Baltimore when he came out of the game after eight scoreless innings of three-hit, seven-strikeout ball only to watch the game go 15 innings before the Yankees finally pulled it out, Colon took care of business for himself Monday.

His pitch count was still a manageable 96 entering the ninth inning, and Colon remained on the mound after he gave up a leadoff double. The runner got to third base but no farther as the A’s for a second time in the game wasted a leadoff double.

The other occasion was back in the second, one inning after the Yankees had staked Colon to a 3-0 lead. The veteran righthander, who pitched a game reminiscent of his 2005 American League Cy Young Award season, set the tone of the game in that inning by keeping the runner at second by getting a foul pop, a strikeout and an infield out.

That began a stretch of 12 consecutive outs that Kevin Kouzmanoff ended with a leadoff single in the sixth. Colon ran off six more outs in a row before yielding another leadoff hit, an infield single by Kurt Suzuki in the eighth. Mark Ellis followed with a grounder up the middle that Colon wisely let go past him to shortstop Derek Jeter, who fielded the ball, stepped on second and threw to first to finish off a double play.

Except for some warm-up throws by Joba Chamberlain in the ninth, the bullpen was quiet. After being forced to use his relief corps for 7 2/3 innings in Saturday night’s 12-inning loss at Seattle, Yankees manager Joe Girardi enjoyed watching Colon and CC Sabathia combine to pitch 17 of the next 18 innings. Only Lance Pendleton’s mop-up job for CC Sunday counted as a work day for the bullpen.

The victory was welcomed by Colon, who had not had a winning decision in his previous five starts and was 0-2 with a 4.60 ERA during that stretch. Colon’s first victory since April 27 got his season record even at 3-3 to go with a spiffy 3.26 ERA.

In what has been a habit for the Yankees on this West Coast trip, they struck early against the starting pitcher, in this case Trevor Cahill, who got off to a 6-0 start this year but is now winless in his past four starts despite a decent 3.51 ERA during that stretch. With an offense ranked 12th among the 14 AL teams, Oakland leaves little margin for error to its pitchers.

On the 16th anniversary of his first major-league hit, Jeter opened the game with a knock and scored one out later on Mark Teixeira’s two-run home run. That made it 16 jacks for Tex, who tied Curtis Granderson for the club lead and passed the center fielder in RBI, 38-37. Teixeira is on a homer binge lately with four in his past five games and seven in his past 11. Tex hit 10 homers in May. He didn’t get to 16 home runs last year until July 9.

Colon hadn’t stepped on the rubber yet, so who knew that would be all the runs the Yankees would need. Robinson Cano mae it 3-0 with a double to score Alex Rodriguez, who had walked. Jeter and Francisco Cervelli, who caught while Russell Martin nursed a sore left foot, supplied pad-on runs with late-inning sacrifice flies.

Cervelli sure didn’t act like a catcher on the bases. He had two steals, as did Brett Gardner. The duo’s running in the seventh after drawing walks helped the Yankees to a run without a hit. The rest was all Colon, who made this Memorial Day memorable.

I’ll be out of town the next few days to attend the Cooperstown Symposium on Baseball and American Culture, an annual event at the National Baseball Hall of Fame where academics and other baseball aficionados gather to discuss seriously through individual presentations and panel groups the connection between the game and the American experience. I am honored to give the keynote address. I only hope my delivery is as effective as that of Bartolo Colon.