For the first time in 103 years Orient have won their first four games of the season after first-half goals from Moses Odubajo and David Mooney - whose successful 37th-minute penalty came six minutes after strike partner Kevin Lisbie had missed from the spot - earned them the spoils at Brisbane Road.
The victory sees Orient climb above Wolves, who beat Crawley on Friday, and into top spot although they are level on 12 points with Peterborough.
Posh maintained their perfect start with a 5-0 mauling of 10-man Tranmere at Prenton Park.
Grant McCann dispatched the subsequent penalty and record signing Britt Assombalonga - with his fourth goal for the club - and Mark Little added further efforts in the second half.
Brentford are in fourth spot after Clayton Donaldson's first goal of the season earned them a 1-0 home win over previously unbeaten Walsall, while a point further back are Bradford following another memorable day for their striker Nahki Wells.
Wells scored for the eighth consecutive game to break a club record and put Bradford ahead at home to Sheffield United and the 23-year-old then added a second late on to complete a 2-0 win.
At the foot of the table, James Dunne's injury-time goal earned Stevenage their first points of the season and inflict a third defeat in four games on opponents Notts County.
Relegated Bristol City are still searching for their first triumph despite Sam Baldock netting twice against former club MK Dons.
Baldock twice put City ahead with goals in the 36th and 66th minutes but the home side hit back both times through Patrick Bamford (52) and Samir Carruthers (69) as the game ended 2-2.
That was the same scoreline in the matches between Swindon-Gillingham and Rotherham-Shrewsbury.
Like rivals Bristol City, Swindon twice led against Gillingham through goals from Nathan Byrne (12) and Nathan Thompson (68) but they were pegged back both times from efforts by Danny Kedwell (18) and Cody McDonald (85).
At New York Stadium, Daniel Nardiello came off the bench to rescue Rotherham's unbeaten record before seeing red.
Tom Bradshaw (63) had threatened to give Shrewsbury victory with his first away goal since April 2011 after Jon Taylor (21) earlier headed the visitors in front before Alex Revell (57) fired in an equaliser.
However, Nardiello drew Rotherham level in 69th minute before being sent off late on.
Also, Oldham survived a missed penalty from former striker Lee Hughes to beat Port Vale 3-1, with Adam Rooney netting a brace for the victors.
Rooney headed Oldham in front (15) but Jennison Myrie-Williams equalised in style (31) before Hughes had his spot-kick saved (38). Rooney made him pay from close range (57) before James Dayton added a third (77).
- Sports & Recreation
- Tyrone Barnett
- Moses Odubajo
- David Mooney
- Kevin Lisbie