BALTIMORE -- Bartolo Colon had his sites set on a complete-game shutout Sunday against the Orioles, and then a series of inexplicable events not only unhinged the game, but the entire three-game series for the A's.
With the A's leading by two runs in the ninth, Colon gave up two choppy infield singles and committed a throwing error that allowed runners to advance to second and third. Grant Balfour entered and immediately gave up the tying two-run double to Matt Wieters. After an intentional walk to Chris Davis, Balfour then allowed a walk-off, three run homer to Wilson Betemit, and the A's were stunned 5-2 in front of 31,793 at Oriole Park.
The A's (11-12) lost two of three to the Orioles (14-8) to begin an arduous nine-game East Coast road trip that includes games against Boston and Tampa Bay. The loss also dropped the A's below .500, ensuring they will not finish the month of April with a winning record, something they have not done since 2008.
"The momentum was going their way, and I fell behind," Balfour said. "Betemit put a good swing on it, and that's the way it goes. Today is a day I have to move on from. They're a good team over there. They're no slouch, and you have to make pitches, because you got guys who can hit."
Colon was effective for the third consecutive start, allowing just seven hits, with four strikeouts and one walk. He was charged with two runs. Colon once again relied on his command, and is averaging just 1.31 walks per nine innings this season -- fifth-best in the American League.
"I felt good the whole game, even in the ninth inning," Colon said through an interpreter. "I rushed a little bit [on the throwing error]. After I've saw the ball, I thought I had a chance at the runner."
The Orioles' Tommy Hunter was also effective, allowing two runs on seven hits with two strikeouts and one walk. Hunter was the recipient of some solid defense, including a 3-6-3 double play initiated by first baseman Mark Reynolds, a diving catch by Adam Jones that robbed Eric Sogard of a hit, and Nolan Reimold saved a potential home run.
As the A's offense has continued to struggle, the pitching has carried the team so far this season. The A's entered Sunday's game having compiled a 2.78 ERA over the last 10 games and have an ERA of 3.02 on the season -- second-best in the American League.
On the other hand, Oakland has scored the fewest runs in the American League with 67, which is a franchise low through 23 games. The previous low was 73 runs, set in 1968.
A's right fielder Josh Reddick entered the game batting .421 at Camden Yards, and picked up two more hits and scored the game's first run on a Yoenis Cespedes double in the sixth. Seth Smith then increased the A's lead to 2-0 with his second homer of the season in the seventh.
"There' s not a guy in this room where this hasn't happened to his team before," Smith said. "You move on. It stinks today, but we'll get up tomorrow and try to win another game."
The Orioles threatened in the seventh when Nick Markakis led off with a double. Colon, however, buckled down and struck out Jones before retiring Wieters on a fly ball to center field and Wilson Betemit on a popup to shortstop.
"He's got such a strong hand, such strong fingers," Orioles manager Buck Showalter, who is now one game shy of his 1,000th win, said of Colon. "He's got like four different pitches. He' tough."
The A's won Friday's series opener 5-2, but lost 10-1 on Saturday.
"I thought [Colon] pitched great," said A's manager Bob Melvin. "[Balfour] didn't have a whole lot of room for error there. He's got to be fine. He's gone away, and it looked to me like Wieters hit a pretty good pitch. It just didn't work out. Some games just don't work out for whatever reason. It's not something you can dwell on."
Todd Karpovich is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.