M&T Bank Stadium is so tough to play for opponents, the Ravens have won 13 in a row and 21 of their last 22 home games.
During the Ravens' 23-17 victory over the Cleveland Browns, they crowd of 70,000-plus was worked into a lather by the presence of Orioles past and present.
Orioles manager Buck Showalter was in attendance in a luxury box with Adam Jones, Brady Anderson and Cal Ripken among others.
The Orioles are in second place in the American League East, just one game behind the New York Yankees with six games remaining going into Friday night's three-game series with the Boston Red Sox.
Seeing Showalter was a surprise.
"That was big," said Harbaugh of the energy boost their presence gave the crowd when highlighted on the big screen. "I think the world of that team. I like their coach. He does a great job. The play fundamentally sound baseball."
Despite his laser-like focus, Harbaugh admitted during the Browns game that he sneaked a peak at the Yankees final score. They'd lost 6-0 to the Toronto Blue Jays.
"This is a special team, man. How many close games have they won this year? I think they set a record, right? One-run games, extra-inning games, finding a way to win," Harbaugh said. "That's something we can look at as a team too and say, 'You know what? That's what we did a little bit last night. Find a way to win games.'
"They're welcomed any time. They can come out to practice any time. They're a little busy right now. They need to focus on what they're doing. But the Ravens are big fans of the Orioles."