Adam Jones' solo homer in the top of the 15th inning sent Baltimore past Kansas City, 4-3, in the opener of a two-game series Wednesday.
The Orioles improved to 5-0 in extra inning games on the road this season.
"Fifteen innings? That's a long game, man," said Jones. "But it starts with our pitchers. They give us the opportunity."
J.J. Hardy added three hits with an RBI and Wilson Betemit homered for the Orioles, who have won two in a row and four of six.
Kevin Gregg (1-1) tossed a scoreless 14th frame for the win, and Jim Johnson locked it down in the bottom of the 15th for his 13th save.
Humberto Quintero hit a two-run single for the Royals, whose four-game win streak came to an end.
Nathan Adcock (0-1) took the loss after serving up the deciding blast. It wiped out a stellar performance over five relief frames.
Jones put the visitors ahead to stay by belting Adcock's one-out offering into the seats in left.
Johnson allowed a two-out single to Johnny Giavotella but induced a game- ending grounder to second from Alex Gordon.
"Who wins those (games) is usually someone who makes an error or someone who hits one out," said Royals outfielder Jeff Francoeur. "You can't say enough about the job that (Nate) Adcock did to give us those innings, quick ground ball outs and everything. We couldn't muster up anything either."
The Royals broke through in the fifth. Francoeur doubled to start, Alcides Escobar was plunked with one out, both moved up on a Chris Getz grounder and Quintero's base hit brought both in.
In the eighth, Hardy doubled off Kelvin Herrera and Nick Markakis followed with an RBI double to get the O's within one.
Kansas City gave itself some breathing room in the home half as Billy Butler singled with two down and pinch-runner Mitch Maier came around to score on a Gordon double.
But the O's kept things going with a two-run ninth. Betemit hit a one-out solo homer and Chris Davis followed with a single. Royals closer Jonathan Broxton bore down and got Rob Andino to fly out, but Xavier Avery singled to put men on first and second and Hardy plated pinch-runner Ryan Flaherty with the tying run.
Neither team put together a serious threat through the 14th, though Baltimore left a runner at second in both the 12th and 13th innings.
Baltimore has won five of its last seven matchups with KC...Wednesday's contest marked the longest game between the two clubs since June 15, 1996 when the Royals topped the Orioles by a 7-6 count in 16 innings at Kansas City...O's starter Tommy Hunter allowed seven hits and two runs over seven innings, while his Royals counterpart Felipe Paulino tossed seven scoreless frames, scattering five hits and fanning nine...Earlier Wednesday, former Orioles pitcher Kevin Hickey passed away at the age of 56.