There were missed connections with his wide receivers early. There were squandered opportunities on third down. And then, after the offense finally started to gain forward momentum late in the first half, there was the pick-six that sent the game spinning out of their control.
In that Week 15 meeting, Anquan Boldin was shut out by the Broncos secondary and Torrey Smith, who had just one catch that day, was knocked out by a concussion early in the third quarter. His top wide receivers blanketed, Flacco played one of his poorest games of the season.
"I don't know how much you can pay attention to that game and say, 'Hey, we didn't get the ball to this guy or we didn't get it to that guy,' the quarterback said. "It was just a weird one."
The Broncos, with a ferocious pass rush and a savvy secondary, ranked third in the NFL in pass defense this season, and the Ravens were one of many opponents that watched their game plans crash and burn during Denver's 11-game winning streak. To fare better this time, the Ravens wide receivers must beat the press before Flacco is buried deep in a pile of Broncos at the intersection of blue and orange.
"It's all about, and I say it all the time, it's all about executing," Smith said. "It's a great defense over there. They have a lot of playmakers, but it's on us just to go out and execute."
That 34-17 win was a dominant performance by the Denver defense. The Broncos held running back Ray Rice to 38 yards on 12 carries. With the Ravens rendered one-dimensional, Flacco was sacked three times and hit or harassed on nearly half of his dropbacks, according to Pro Football Focus, which credited him with 10 plays where he forced a pass or overthrew or underthrew his target.
Ravens wide receivers caught just eight of the 19 passes thrown their direction for 115 total yards.
One of those errant passes, one intended for Boldin late in the first half was pounced on by cornerback Chris Harris, who returned the interception 98 yards for a spirit-squishing touchdown.
"Obviously, it's a heck of a defense," said Jim Caldwell, whose first game as Ravens offensive coordinator was that day. "Not only did they thwart us in that particular game, but they've done so the entire season to every team they've faced for the most part. They are a real challenge."
Led by cover cornerback Champ Bailey — and aided by a pass rush led by Defensive Player of the Year candidate Von Miller — the Broncos have allowed an average of 132.4 receiving yards per game to wide receivers.
They often disrupt wideouts at the line of scrimmage with press coverage, a strategy that also gave the Ravens problems against the Philadelphia Eagles, Kansas City Chiefs and Houston Texans.
"I wouldn't say [they are] physical, but they do like to press," said Ravens wide receiver Jacoby Jones, pointing out that there may be opportunities for big plays down the field if the Broncos miss their jams.
Against the Ravens, the Broncos stuck with wide receivers in man coverage and mixed in some clever zone coverages when the Ravens were in third-and-long situations, a regular occurrence.
The Ravens were just 1-for-12 on third down and 0-for-2 on fourth down. On those plays, Flacco was 3-for-13 for 29 yards. Overall, Flacco completed 20 of his 40 attempts for 254 yards and two touchdowns, but when the Broncos took a 17-0 lead into halftime, they had more interception return yards (98) than Flacco had passing yards (78).
"They do some funky things on third down where they play zones and [blitz] some different guys," Flacco said. "I think the big thing for us will be to hit guys early and let them do some damage running after the catch."
Tight end Dennis Pitta, who led the team with seven grabs for 125 yards and two touchdowns, gained 63 of those yards after the catch. Flacco said that, in hindsight, he wished he would have gotten the ball out of his hands quicker, giving his wide receivers — who combined for just 39 yards after the catch — a chance to catch the ball short of the marker and try to break free for a first down.
Tandon Doss said he and his fellow wide receivers can do their part by showing more urgency.
"We have to get in and out of our routes, get to our spots, get to our depths quickly because we know that they've got some guys up front that can bring it," he said. "We just have to speed it up a little bit."
The Broncos held Boldin without a catch for the second time in his career, and after Sunday's wild-card win over the Indianapolis Colts, he admitted that he was hoping for a rematch with the Broncos, vowing, "We'll make it different."
"He's definitely a guy that when you get him the ball early, he can get going. He can get revved up a little bit, and he's a good receiver obviously," Flacco said of Boldin, who caught five passes for 145 yards and a touchdown against the Colts. "When you get him going and he is coming down with everything, he definitely gets juiced up and it gives us something extra."
Boldin is typically the one Ravens receiver who can consistently bust through press coverage, but Harris did a good job of keeping the veteran within arm's reach when in one-on-one coverage back in December.
Smith was often trailed by Bailey. He saw that as a sign of respect, as Bailey was just voted to his 12th Pro Bowl in 14 NFL seasons. But Smith had just one reception for 14 yards before suffering a concussion when he slammed his head on the turf while catching a deep pass out of bounds.
Still, after watching the tape, Flacco remains confident that he and his wide receivers will come together and produce more big passing plays this time around.
"I think we have good matchups out there if they want to play us one-on-one," Flacco said. "We have pretty good guys who are capable of beating that."