Loan watch: Britt back among the goals
After a blistering start to the campaign in Essex, Assombalonga's form had hit the buffers in recent weeks.
However, the forward scored an 85th minute winner in Southend's 2-1 victory at Wycombe Wanderers on Saturday.
Assombalonga was also booked.
In League One, Stephen McGinn and Steve Beleck went head-to-head as Shrewsbury Town took on Stevenage.
The Shrews won 2-1, with McGinn playing the full 90 minutes for Graham Turner's side.
Beleck entered the fray as a 69th minute substitute, replacing Marcus Haber.
Chris Iwelumo started for Oldham Athletic, who beat Portsmouth 1-0.
The 34 year-old Scot was replaced after 66 minutes by F.A Cup hero, Matt Smith.
Elswhere in the third tier, Carl Dickinson played the full 90 minutes for Coventry City, who were beaten at home by Crewe.
The left-back was booked at the Railwaymen pulled off a surprise 2-1 win against the League One high-fliers.
In the Blue Square South, Piero Mingoia was a 65th minute substitute as Boreham Wood drew 1-1 at home to Dover Athletic.
Finally, Lee Hodson did not make Brentford's matchday 18 as they drew 0-0 with Walsall, whilst Aaron Tumwa was not involved in Wealdstone's stalemate with Hendon.