Kevin Lisbie scored against his former club as Leyton Orient beat Colchester to maintain their perfect record and best-ever start to a season.
David Mooney, who had a loan spell at the U's in 2010-11, fired the visitors ahead from close range.
Colchester levelled against the run of play when Jabo Ibehre fired past Jamie Jones from just inside the area.
But Lisbie then headed the O's back in front and they held on to claim their fifth consecutive win this term.
The victory was also Orient's first at Colchester since 1951.
VIEW FROM THE DRESSING ROOM
Leyton Orient manager Russell Slade told BBC London 94.9:
"I was just thinking about trying to galvanise the boys and to get a win. It was a tough game obviously. It was going to be our toughest game on the back of the 120 minutes that we had on Tuesday.
"The big thing was, I was asking them in the team talk to go that extra mile, and there's not much traffic in that extra mile, and a lot of my players got there today.
"Our in-form strikers, they're in the form of their lives at the start of the season, which is what you both want.
"They've both got five, and they're looking so potent at the minute it's frightening."
Colchester United 44 Walker 03 Dickson 04 Okuonghae 18 Eastman 23 Olufemi 02 Wright (Gilbey - 71' ) 06 Eastmond 07 Watt 11 Sears (Morrison - 78' ) 21 Massey (Wright - 71' ) 17 Ibehre Substitutes 01 Cousins 05 Thompson 26 Spence 14 Bond 22 Gilbey 09 Morrison 30 Wright Leyton Orient 01 Jones 02 Omozusi 05 Cuthbert 06 Baudry 15 Clarke 04 Vincelot 07 Cox 08 James (Bartley - 78' ) 11 Odubajo 09 Lisbie (Batt - 76' ) 10 Mooney Substitutes 12 Larkins 17 Vanderhyde 14 Batt 16 Lee 20 Gorman 21 Bartley