Rickie Lambert took his tally for the season to 18 in the 26th minute when he headed home Ryan Dickson`s teasing cross.
And Lee Barnard secured the points when he tapped in a cross from strike-partner Lambert three minutes before full-time.
Saints lie second in the table and Adkins said: "This was a tremendous victory for us.
"Orient is always a difficult place to come to and they have been in fantastic form this season.
"It's now up to us to keep going in an effort to make sure of promotion. That is what the players and the club deserve and certainly the fans."
Source: PA
Source: PA