Flacco out-dueled Aaron Rodgers in just the third NFL regular-season game to feature two 40-something starting quarterbacks.
The 41-year-old Rodgers threw for 244 yards with four touchdowns, but was intercepted twice.
Rodgers escaped pressure in the pocket to connect with tight end Pat Freiermuth for a 68 yard touchdown with 2:31 remaining that put Pittsburgh up 31-30.
But the 40-year-old Flacco piloted an eight-play, 52-yard drive that included a 28-yard pass to Tee Higgins to set up McPherson's final strike.
Cincinnati wide receiver Ja'Marr Chase caught 16 passes for 161 yards and a touchdown and Higgins finished with six catches for 96 yards.
The back-and-forth battle saw the Steelers lead by 10 early in the second quarter and the Bengals ahead by the same margin less than a minute into the fourth.
"This is a huge win, we needed it," said Cincinnati coach Zac Taylor, whose Bengals hadn't won since star quarterback Joe Burrow suffered a toe injury in week two.
With backup Jake Browning struggling, the Bengals acquired Flacco -- a Super Bowl winner with Baltimore in 2018 -- from Cleveland earlier this month.
The Steelers fell to 4-2 atop the NFC North division, the Bengals improving to 3-4 to close the gap.
The Ravens and Browns are languishing at 1-5.
© 2025 AFP