Just past the half hour mark, referee Ian Cooper awarded the visitors a spot-kick for an apparent shove by Mark Haines on Matthew Patterson to the stunned silence of the home crowd.
Bennett slotted the penalty past Nicky Eyre comfortably and in the aftermath of the goal, manager Mark Hawkes was sent to the stand for comments made to the referee's assistant on the near side.
The incident had the Clarets rattled but the home side got through to half time and after the introduction of Joe Ward Chelmsford put the Hampshire side under severe pressure in search of an equaliser.
Nathan Ashmore saved twice in a minute - first from Luke Callander and then from Ward from the resulting corner - before the home side were given a lifeline when Rory Williams saw red for a second bookable offence.
But Chelmsford were unable to make their extra man count as Ward saw his close range effort desperately cleared off the line, and both Michael Cheek and Sam Gregory were unable to find the target late on.
So after a promising pre-season campaign the league season began with a bump for Mark Hawkes’ side, although they can consider themselves extremely unfortunate to have not come away with at least a point.
The game began with all the hallmarks of a cagey league opener, sprinkled with a few tough but fair tackles from both sides early on.
Overall Gosport arguably shaded the opening quarter of the game, without having to unduly trouble Nick Eyre in the City goal.
Only a long range effort from Steve Ramsey forced Eyre into action diving to his right, with the visitors also having Sam Pearce and Daniel Wooden sending attempts off target.
But just after the half hour mark the blue-touch paper was lit as the referee awarded Gosport a controversial penalty to the surprise of a stunned crowd at Melbourne Stadium.
The penalty was awarded for a shove on Matthew Patterson by Mark Haines with referee Ian Cooper pointing to the spot. Justin Bennett duly accepted the opportunity, striking low to Eyre’s right to give the visitors the lead.
In the aftermath of the incident, manager Mark Hawkes was sent to the stand for his response to the penalty decision which on the whole unsettled the Clarets side.
With the home side clearly rattled Gosport created couple of chances to put daylight between the two teams with Thomas Dunford having the best of them scuffing an effort wide from a corner.
Having gotten in at half time with no further damage, Chelmsford sent on Joe Ward 10 minutes into the half which added a different dimension to the home side’s attacks.
Ward’s direct running was putting the Gosport back line under pressure as the hosts went in search of an equaliser.
Gosport can have their goalkeeper, Nathan Ashmore, to thank for keeping their side in front as he made two smart saves in the space of 60 seconds midway through the half.
The first save came at his near post after Luke Callander had manufactured some space in the area to get his shot away. From the resulting corner, Glen Southam’s out-swinger found Ward who lashed a volley low and hard only to be saved by the feet of Ashmore.
Chelmsford were beginning the turn the screw with Gosport failing to apply any pressure of their own on Eyre’s goal, and Michael Cheek was next in line try his luck but failed to hit the target after the pull back from Lee Sawyer was played agonisingly behind the striker.
With just over 10 minutes of normal time remaining, the Clarets were awarded a lifeline as Gosport’s Rory Williams was shown a second yellow card for a cynical challenge on Ward.
But with the extra man the home side were unable to capitalise despite creating two glorious chances towards the end of the game.
Ward will wonder how on earth his effort from inside the six yard box did not cross the line after the ball fell to him at the near post. The young striker lashed the ball towards goal expecting the net to bulge only for it to be cleared.
And deep into stoppage time another substitute, Sam Gregory, found himself through on goal with only Ashmore to beat, but Gregory skied his half-volley high over the cross bar as the 10-men of Gosport held on.
"Very, very disappointed about the result" said Assistant Manager Steve Smith at full time. "First half we played a diamond and didn't think we really created enough and got at them. In saying that I thought they got a real bad decision go against us - I don't know what it (the penalty) was for.
"Second half we changed the formation, went 4-4-2 and put Wardy (Joe Ward) on and I thought we started to get at them. On another day we could have won 2-1, 3-1, but we created enough chances second half to win the game."
Regarding the penalty incident, skipper Mark Hughes commented saying "the ref said he (Mark Haines) pushed him when clearly our man won the header and Hainesy was just blocking the guy. I think everybody knows it wasn't (a penalty) - even their fans' reaction was laughable too.
"But I think we let it affect us for a little while. We regrouped at half time and the response was good second half with enough chances to win two games."
By Scott Hatley
1. Nicky Eyre
2. James Love
3. Leon Redwood
4. Mark Hughes (C)
5. Mark Haines
6. Marvin Ekpiteta
7. Lee Sawyer
8. Glen Southam
9. Luke Callander (Sam Gregory 72’)
10. Michael Cheek
11. Christian Smith (Joe Ward 56’)
Unused Subs: Justin Miller, Harry Morgan, Niklas Freund
1. Nathan Ashmore
2. Lee Molyneux
3. Rory Williams
4. Michael Carter (Robbie Matthews 84’)
5. Ben Gerring (Brett Poate 42’)
6. Sam Pearce (C)
7. Thomas Dunford
8. Steve Ramsey
9. Matthew Patterson
10. Justin Bennett (Daniel Smith 80’)
11. Daniel Wooden
Unused Subs: Paco Saez, Adam Wilde
Chelmsford: Mark Haines (53' - Persistent Fouling)
Gosport: Brett Poate (45' - Foul)
Sent Off: Rory Williams (Gosport - 79' - Second Yellow Card)
Referee: Ian Cooper (Rochester).
Assistant Referees: Daniel Cook (Braintree), Neil Morrison (Staines)
City Man of the Match: Glen Southam