"The difference between Tuesday and today is confusing," Orient manager Martin Ling said after his side bounced back from FA Cup defeat at Torquay to beat League One leaders Nottingham Forest.
"We haven't been that good on the road, and then we come to Forest and put in a performance like that.
"But it's the second time we've had back-to-back league wins this season - a win on Tuesday against Northampton would lift us out of the bottom four."