Chesterfield marked their return to Sky Bet League One with a deserved 2-1 victory at Leyton Orient with goals from Romuald Boco and Eoin Doyle before Darius Henderson netted a late reply for the home side.
It took the Spireites just six minutes to go in front when Boco pounced on hesitancy in the home defence and drilled a low shot into the left-hand corner from 15 yards.
The visitors, who always looked dangerous on the counter-attack, might have doubled their lead nine minutes later when the dangerous Doyle slipped past two defenders onlty to stab his shot against an upright as he attempted to lob O's goalkeeper Adam Legzdins frorn 10 yards.
Visiting goalkeeper Tommy Lee was finally called into action when he blocked a shot from David Mooney with his feet before producing a superb double save in the 24th minute.
Lee spread himself to block a shot from point-blank range by Dean Cox and when the ball fell into the path of Kevin Lisbie, he again parried the effort.
However, he rode his luck when a Lisbie header from six yards hit his body.
Despite enjoying the greater possession after the break and with Chesterfield defending deeper, the O's created little threat.
And the home side and fell further behind when the impressive Doyle got between two defenders in the 78th minute and lobbed the ball past the advancing Legzdins.
Substitute Henderson gave Orient a late consolation eight minutes from time after Lee had spilled Cox's free-kick and the striker was given the simplest of chances from inside the six-yard box.