The Athletics, remaining the only big league team unbeaten against another, improved their all-time record against Pittsburgh to 10-0.
On other fronts, it was an all-around streak-buster.
It brought to an end two eight-game winning streaks: Locke's, since dropping his first decision back on April 7, and the Pirates' in Interleague Play, since a 6-5 loss in Detroit on May 27.
Also, the Bucs had taken their last 10 one-run games at home, that particular string dating back to early May.
"Losing any time makes you appreciate winning," Locke said. "But winning or losing is the one thing [pitchers] can't control. We battled to the end like always; that's what I always expect of these guys."
This latest loss to the A's heightened the recent offensive frustrations of the Pirates, who have scored five total runs in three consecutive defeats and dropped a half-game behind the St. Louis Cardinals in the division race.
Grant Balfour got the official save of Colon's 12th win -- but the practical save belonged to center fielder Coco Crisp.
The Pirates had already aborted Colon's shutout -- on Jose Tabata's RBI infield single with two outs in the seventh -- and still had two men on base when Andrew McCutchen teed off on a fastball and ripped it to left-center. It had at least tie game written all over it.
But McCutchen insisted later: "The minute I hit it, I knew [Crisp] would catch it. That's Coco Crisp -- he's fast. I told myself, 'I'm catching that ball, too, if I'm out there playing.' Off my bat, I knew it had a chance to fall -- but there was more of a chance he was gonna catch it."
Crisp flew through the air for an inning-ending grab of the gap-seeking liner.
"When he hit it, I didn't think he had a chance to get to it," Oakland manager Bob Melvin said. "I've been around Coco long enough to know he can get to some balls. But that one was terrific. That's the play of the year. I think that's where the game was decided."
No argument from the victim.
"It was a game-saver for them," said McCutchen, who earlier had extended his hitting streak to 10 games. "It happens. I hit the ball hard, just didn't hit a hole. Otherwise, it's a totally different game. But that's the way it goes. There's nothing you can do about it, but keep playing."
Locke tendered his sixth "high-quality" start of at least seven innings allowing no more than two earned runs. In seven innings, he gave up three hits and two runs, with three walks and four strikeouts.
"Came as advertised," Melvin said of the lefty. "You look at him, he's not afraid to pitch inside. He throws his changeup whenever he wants. He's got a breaking ball that he can bounce and throw for a strike. He really commands and bullies both sides of the plate with the way he pitches inside to righties."
Colon, who had won eight straight until losing a tight one to the White Sox on Wednesday in his previous start, also went seven, on a yield of seven hits and one run while walking one and fanning five.
"He was built to pitch," said Pirates manager Clint Hurdle, returning Melvin's compliment. "That's what he's been doing for a long time. This guy's in a good place. He's cut it down to three pitches. His fastball's got life. Sink when he wants it, and he's got that four-seamer that can stay up in the zone. He was built to pitch."
The A's first hit turned into the game's first run, but only after Russell Martin nearly pulled off one of his more amazing plays. With one away in the fourth, Jed Lowrie doubled to right-center and took off for third base when Locke's 1-1 pitch to Josh Donaldson skipped through and about 10 feet behind Martin. The catcher quickly retrieved the ball and unleashed what appeared to be a hopeless throw. But not only was it placed perfectly, it was a little too good: Pedro Alvarez gloved it, but his swipe tag crossed in front of the bag before Lowrie's foot got there.
"Ninety-nine times out of 100, I'll tag him," Alvarez said. "It's just one of those plays, you react, and either you get him or not."
Safe on the wild pitch, Lowrie then came in on Donaldson's sacrifice fly.
Oakland did not put two men on base until the seventh, when the same pair was at the root of the trouble. Lowrie and Donaldson led off with consecutive singles, leading to a two-out, bases-loaded walk of Derek Norris that doubled the A's lead to 2-0.
"That's what will stick out for me -- walking Norris," Locke said, adding that of the deciding inside fastball, "10 times in a row, I'd throw the same pitch again. I was a little off on that spot, but it happens from time to time.
"Really, I wouldn't change anything about [the entire outing]. Everything I did, I'd take it out there for the next start."