A disappointing second-half against Toronto FC saw Columbus Crew SC drop from No. 1 in the most recent MLSsoccer.com and ESPN.com Power Rankings.
See below for the respective sites' explanations.

MLSsoccer.com: 4th
Previous ranking: 1st
"The Crew are still atop the Supporters’ Shield standings, but a fall from the Power Rankings Peak™ comes after a 3-1 setback against Toronto. Keep an eye on the big picture, though, because that snapped a six-game unbeaten streak and they’ve done this with midfielders Lucas Zelarayan and Darlington Nagbe both missing time."
ESPN.com: 3rd
Previous ranking: 1st
"The Crew's three-week reign on top of MLS Power Rankings came to an end following their 3-1 defeat to Toronto -- the most goals that the league's best defense has conceded in a single game all season."