0-0 with just four minutes left, Duffy smashed home a rocket before jumping into the away end.
“It was world class,” Blackburn boss Paul Lambert said. “If a striker had scored that, they’d be jumping through hoops. It was a brilliant goal from the big man.
“I think his performances have been very, very good so to top it with that kind of goal was exceptional.”
Elsewhere, Eoin Doyle got on the end of a cross from fellow Irishman Greg Cunningham to rescue a 1-1 draw for Preston against QPR. Doyle’s goal came late in the day but he felt his side warranted something from the game.
“We controlled most parts of the game, so I think we more than deserved a point,” Doyle said. “It was a terrific ball in and I managed to get on the end of it.”
Leon Best continued his recent renaissance by netting Rotherham’s winner in the 1-0 victory at Mick McCarthy’s Ipswich.
Millers boss Neil Warnock said: “Leon Best has come in and I think he is the only player on that pitch who could have scored that goal — it was a better one than what people might think.” McCarthy said: “We deserved to get booed off. It was a poor performance but I take a big part of the responsibility for that.
“I left the team as it was on Tuesday (a 2-0 win over Blackburn) when in hindsight, I should have changed it.”
Chris Hughton saw his Brighton side climb to second after a 2-1 win at the MK Dons.
Paddy Madden was the only Irish goalscorer in League One, his 20th goal of the season helping Scunthorpe to a 1-1 draw with Chesterfield.
In League Two, goals from James Collins and John-Joe O’Toole helped runaway leaders Northampton to a 3-2 win at Stevenage while a brace from Callum O’Dowda inspired second place Oxford United to a 3-0 win at Barnet.
Elsewhere, Rhys Murphy scored in Wimbledon’s 2-1 win over York City while goalkeeper Barry Roche was sent off in Morecambe’s 1-0 defeat at Leyton Orient.
In the Scottish Championship, Anthony Stokes scored but Hibs lost 2-1 to Raith.