Zlatan Ibrahimovic scored the perfect hat-trick as LA Galaxy closed the gap on LAFC to nine points at the top of MLS.
Gonzalo Martinez came off the bench to break the deadlock in the 89th minute before Josef Martinez sealed Atlanta United's victory.
Philadelphia Union bounced back from their worst loss of the season – a 4-0 rout at the hands of Real Salt Lake – to beat Chicago Fire 2-0.
LA Galaxy superstar and former Manchester United striker Zlatan Ibrahimovic joked about internet meme #StormArea51.
Jefferson Savarino guided Real Salt Lake to a crushing victory over Philadelphia Union on Saturday.
The San Jose Earthquakes were victorious in the California Clasico against the LA Galaxy again.