On the opening weekend of the 2017-18 Premier League campaign, the 26-year-old turned a Fernandinho cross into his own net.
Another slice of bad luck against United in his latest outing saw him hit the wrong target once again, as he deflected an Ashley Young effort beyond Mat Ryan.
2 - Lewis Dunk is the first player in Premier League history to score an own goal versus both Man Utd and Man City in the same season. Slam.— OptaJoe (@OptaJoe) November 25, 2017
Brighton were already a goal down when Dunk put past his own goalkeeper against City, with the Premier League leaders recording a 2-0 win.
His involvement against United proved to be pivotal, though, as the Red Devils edged a keenly-fought contest.
The Seagulls had held their own for long periods at Old Trafford, but Young’s strike forced Dunk into attempting a block and the deadlock was suddenly broken.
While the Brighton native will be disappointed to have recorded a rare double, he has impressed alongside his team-mates since stepping up into the Premier League for the first time.