CINCINNATI -- Baltimore Ravens quarterback Joe Flacco showed no signs of a back injury. The only pain he felt came from playing on an offense that went ultra-conservative in Sunday's 20-0 win over the Bengals.

The Ravens reigned in the offense so much that Flacco didn't even complete a pass in the second half. According to ESPN Stats & Information research, it was the first time in six years that a team won without completing a pass after halftime, a distinction that didn't go over well for a former Super Bowl MVP.

"It wasn't that fun to play on offense [Sunday] -- just to be honest," Flacco said. "I was 9-for-17, and I threw for a hundred and a couple [121] yards . I mean, it's not that fun. I'd rather throw for 350 and win 42-0, not 20-0. But it's fun to win, and that's the most important thing."

While Flacco didn't enjoy all the playcalling, this was probably the optimal game for a quarterback who only returned to practice from a back injury eight days before the opener.

The Ravens were conservative with Joe Flacco in Week 1 after the quarterback missed most of the preseason. Aaron Doster/USA TODAY Sports

The Ravens jumped out to a 17-0 lead by halftime, and Flacco only dropped back three times the rest of the way. As a result, Flacco finished with his fewest completions (nine) and attempts (17) for a full regular-season game.

His performance was important in that he answered questions about his injured back. Flacco took a handful of brutal hits, including one that led him to get tested for a concussion. Every time Flacco was knocked and pushed to the ground, he immediately bounced up.

"That's the thing about Joe Flacco, he's really tough," Ravens coach John Harbaugh said. "I'd like to keep him cleaner, obviously. We're going to have to keep working to do that. Joe's just a tough dude, and I'm really proud of him. You've got to respect him."

Flacco's last completion tested that toughness. The Bengals lined up for an all-out blitz on third-and-7 in the second quarter, and Flacco made the throw to wide receiver Jeremy Maclin with seven defenders in his face.

"It was one of those things that I told Marty [Mornhinweg, offensive coordinator], 'If they want to go all-out blitz, that's what I'm going to go to,'" Flacco said. "I looked back and there were no safeties. I said, 'OK, here we go.'"

Maclin, who had a total of seven practices this year, took the short pass and ran 48 yards for a touchdown. Flacco didn't complete another pass for the final 32 minutes.

QUIET FLACCO Joe Flacco has had five games in which he completed 10 or fewer passes in a full game, and the Ravens have won all of them. Year Team Comp-Att Yards Result 2017 at Cincinnati 9-17 121 Won, 20-0 2008 vs. Washington 10-21 134 Won, 24-10 2010 vs. New Orleans 10-20 172 Won, 30-24 2011 vs. New York Jets 10-31 163 Won, 34-17 2011 at Cleveland 10-23 158 Won, 24-10

"Business as usual. He's a professional," Maclin said when asked about Flacco. "He's going to handle himself like one. You didn't see him being timid. You didn't see him out of his element. This is where he belongs. Everything was smooth."

Flacco acknowledged that he missed some throws. He threw a couple of passes that were nearly intercepted. He also let the time run out on the clock twice in the fourth quarter for delay of game penalties.

Still, Flacco delivered a winning performance, despite being sidelined 36 straight days this summer.

"I felt comfortable," Flacco said. "When we're out on that field, it doesn't matter how long you haven't been out there, you feel back at home."