Unlike the preseason when his ankle constantly bothered him and would swell up, Williams said he didn't experience any pain or difficulties.
"It felt good," he said. "It was definitely something to build on."
Williams drew solid reviews from teammates and coaches.
In 56 plays, Williams allowed just one quarterback pressure.
"Bobbie is a veteran guy, love him, love the energy, love the man," center Matt Birk said. "He was great. He's a big, physical player in there. Obviously being a veteran guy, Bobbie can take care of himself. Bobbie stepped in there and played well."
Williams lined up next to left tackle Michael Oher, who had started the first five games next to Harewood.
"Bobbie, he's a good player," Oher said. "He filled in. He's been around for a long time. Ramon is working hard, done a great job. Stuff happens."
The Ravens signed Williams, 36, to a two-year, $2.2 million deal in the spring that included an $800,000 signing bonus.
"I think the decision to start Bobbie was that Bobbie is getting healthy right now, and that ankle is starting to really come around," Ravens coach John Harbaugh said. "Ramon had been playing well. That's the thing I want to make sure everyone understands.
"It's not that we're down about Ramon. It's nothing that Ramon did. He stepped in there and played well for a guy who hadn't played much football at all. But we felt like the experience was something that would benefit us."