"There's still a lot more hard work to come," he said. "I'm feeling better. I still don't feel like I'm where I need to be. I'm just going to keep plugging away."
Drafted by the Orioles in 2003, the right fielder has been one of the faces of the Baltimore franchise, eclipsing the 100-RBI mark twice and boasting a career .293 average.
But this season Markakis has strayed from being the presence at the plate Baltimore fans have come to expect. He's batting .241 and had gone 87 at-bats without an extra-base hit entering Friday.
Although Markakis is still not where he wants to be offensively, he took a step in the right direction against the Rays on Friday night, recording a career-high six RBIs.
The 27-year-old's grand slam in the second and two-run double in the eighth accounted for all but one of Baltimore's runs in a 7-0 win.
"Everybody knows the work that Nick's been putting in," manager Buck Showalter said. "He feels such a responsibility to the team and the Orioles. We see it. He doesn't wear it on his sleeve. But he grinds it, almost to a fault. That's why you love him. He's a piece for us, the things he does to give himself a chance to be successful."
It was the first grand slam Markakis has hit since April 17, 2009, at Boston off Brad Penny, and his first double dating back to May 15 at Tampa Bay.
This season, his batting average, on-base percentage and slugging percentage are the lowest of his career.
But with one swing that sent a 73-mph curveball into the right-field flag court, it looked as if the Markakis of yesteryear had returned -- or at least had begun the journey back.
"I'm real happy for Nick to get that hit," Jake Arrieta said. "I feel like he's been one hit away like that, and I know he had at least two hits tonight, that grand slam and double later in the game, that's just great for him. He's a guy that I always want at the plate with guys on base, no matter what the situation is. Regardless of his struggles, he's a very, very good hitter. And tonight he showed it."
Avi Zaleon is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.