Atlanta overcame fellow strugglers and winless Colorado Rapids 1-0 courtesy of Julian Gressel at Mercedes-Benz Stadium.
Struggling for form since former Inter and Crystal Palace boss De Boer replaced Gerardo "Tata" Martino at the start of the season, Atlanta finally gave its fans something to celebrate on home soil following two draws and a loss.
Gressel's goal with 16 minutes remaining gave Atlanta its second win in five matches, though the defending champion remains 10th in the 12-team Eastern Conference and four points adrift of the top seven while the Rapids are bottom in the Western Conference with just two points.
Atlanta United FC (@ATLUTD) April 27, 2019
It was an eight-goal thriller in Kansas City, where Sporting and nine-man New England shared the points on Saturday.
Sporting KC rescued a draw thanks to Krisztian Nemeth's 83rd-minute equalizer against the visiting Revolution, who had Brandon Bye and Jalil Anibaba sent off in the second half.
New England opened the scoring and led 3-1 and 4-2 thanks to Juan Caicedo's first-half brace before Sporting KC rallied and capitalized on its numerical advantage through Nemeth and Felipe Gutierrez – the pair netting two goals apiece.
Elsewhere on Saturday, the Philadelphia Union lost ground on Eastern Conference leaders D.C. United after a 1-1 draw at Vancouver Whitecaps, FC Dallas played out a goalless stalemate with the San Jose Earthquakes and the lowly New York Red Bulls accounted for FC Cincinnati 1-0.