BALTIMORE -- For three quarters, quarterback Joe Flacco was the hero for the Baltimore Ravens, running for two touchdowns and throwing for another.

Then came the toughest part of the game lately for him.

Flacco is the NFL's worst-rated passer in the fourth quarter through five weeks of the 2015 season, and his struggles in the clutch continued in Sunday's 33-30 overtime loss to the Cleveland Browns.

Joe Flacco completed 2 of 10 passes for 32 yards on Sunday in the fourth quarter and overtime. Patrick Smith/Getty Images

In the fourth quarter and overtime Sunday, Flacco completed 2 of 10 passes for 32 yards. Only one of his pass attempts in the fourth quarter and overtime traveled more than 5 yards past the line of scrimmage, according to ESPN Stats & Information.

Not all the blame can be placed on Flacco for these numbers. He didn't have his top wide receiver (Steve Smith), rookie first-round pick (Breshad Perriman) and top two tight ends (Dennis Pitta and Crockett Gillmore). He was also pressured on six of his 11 dropbacks in the fourth quarter and overtime.

It's been a combination of not having enough time in the pocket and receivers like Kamar Aiken and Marlon Brown not getting open soon enough.

Through five games, Flacco has a passer rating of 56.0 in the fourth quarter, which ranks last among qualified quarterbacks. The only other quarterbacks with a rating below 60 are St. Louis' Nick Foles (58.4) and Tennessee's Marcus Mariota (56.5).

In the fourth quarter, Flacco has completed an NFL-worst 46.8 percent of his passes (29-of-62) for 343 yards passing. He has thrown one touchdown and two interceptions, and his 5.53 yards per attempt is last in the league.

Failing to come through in pressure situations this year has been a recurring theme for the Ravens, whose four defeats have been decided by a total of 17 points.

These results are much different than the ones Flacco typically puts up. In his previous seven seasons, Flacco was the ninth-best quarterback in the fourth quarter with an 89.0 rating. That was higher than Andrew Luck, Matt Ryan and Andy Dalton. This is the best indicator that the Ravens' troubles late in games this year are more of a reflection of Baltimore's supporting cast than Flacco himself.