After J.J. Hardy popped out, Machado hit a flyball to deep center.
"He was challenging me. His best pitch is his fastball," Machado said. "He started with a strike. Then he comes up and in. So I'm down 0-2 real quick. He tried to get me out with a fastball down and in, and I got it up and put it in play."
Mariners manager Lloyd McClendon didn't like what Medina threw Machado.
"It wasn't a good pitch, it was a strike," McClendon said. "He was trying to get a groundout. He went at him with his best stuff. It just didn't work."
Machado also singled and scored in the third inning and had an RBI single in the eighth.
T.J. McFarland (4-2) worked one inning for the victory. His effort came on a day when his grandmother passed away in Chicago. He plans to leave the team beginning Monday for at least three days to attend her funeral.
Zach Britton struck out the side in the 10th for his 20th save in 23 opportunities.
Dustin Ackley had three hits for the Mariners and is batting .375 in 21 games this month.
"They got runners on at the end and they were able to get the sac fly, which was huge," Ackley said. "We just didn't take advantage and they did."
Mariners reliever Brandon Maurer had not allowed an earned run in 10 previous relief appearances, a span of 15 innings, before Baltimore took a 2-1 lead in the eighth.
The Orioles loaded the bases off Maurer with two outs, then Machado bounced a one-hopper to the left side. Shortstop Chris Taylor caught the ball but threw awkwardly and high to second baseman Robinson Cano, pulling him off the bag. It was ruled a hit and Jones scored.
"It was frustrating. I really thought I should have had that. It got away from me a little bit," Taylor said. "I don't think I rushed it, just made a bad throw. I don't have any explanation for it. It just happened."
Orioles reliever Darren O'Day, who had not allowed a run in his previous 14 appearances -- a stretch of 15 1/3 innings -- came on in the eighth to protect the lead.
Mike Zunino connected with two outs for his 15th home run. The tying shot was the Mariners' first home run in six games.
"Darren has been pretty much perfect this year," Showalter said. "We owed him. We picked him up today."
The Mariners got four hits in the second inning but managed just one run. Kyle Seager opened with a single off the wall, but was thrown out at second by right fielder Nick Markakis.
Corey Hart and Zunino singled and Taylor, called up Thursday for his first big league experience, got his first RBI with a double.
Medina lost on his 26th birthday. ... Showalter will give Wei-Yin Chen a few extra days between starts. Chen will next take the mound Friday when Seattle visits Camden Yards. "Wei-Yin had his top pitch count of the year (109 Thursday) and I want to keep guys on turn," Showalter said. ... A player will be called up for Tuesday night's home game against the Angels with McFarland on the bereavement list. ... O's pitching coach Dave Wallace will leave the team this weekend to attend his daughter's wedding. Scott McGregor, a minor league pitching instructor, will take over.
Copyright by STATS LLC and The Associated Press
SEATTLE, WA - JULY 27: Starting pitcher Miguel Gonzalez #50 of the Baltimore Orioles pitches in the first inning...