The two strikers scored within 11 minutes of each other in the first half on an afternoon where City could well have scored many more.
After failing to test Oxford goalkeeper Jack Stevens with a number of early chances a long ball was the key to unlocking the visitors when Mullings beat Stevens to a clearance from Daniel Blanchett, rounding the ‘keeper before composing himself to score.
The Clarets then doubled their lead four minutes from the break when Jeffers out-muscled his marker before sending his shot squirming underneath Stevens to double City’s advantage.
City could well have scored a number more as they hit the woodwork twice through Chris Bush and Phillip Walsh, with Mullings missing a whole host of chances to put the gloss on the win.
It was a welcome three points and performance from Rod Stringer’s who were coming off the back of two straight defeats to St Albans City and Maidenhead United.
The big news going into the match with Oxford was that Ross Fitzsimons was thrown between the sticks straight away having been signed late on Friday from local rivals Braintree Town.
Fitzsimons replaced Joe Welch and was one of four changes for Stringer, bringing back Robbie Willmott as well as Shamir Mullings and Shaun Jeffers to spearhead the attack.
The visitors Oxford have had to deal with financial problems off the field and haven’t made the best of starts to their campaign, and the Clarets put them under the cosh early on with a string of chances.
Robbie Willmott was first to test his arm sending a free kick from the edge of the area over the bar, before Shamir Mullings was picked out by Willmott only for his header to go wide.
Mullings then turned creator as he laid the ball off for Bagasan Graham who screwed his effort wide of the target, before the big number nine found Shaun Jeffers with a pull-back that the former Yeovil striker too failed to trouble Jack Stevens with.
Phil Walsh came close with his flick header from a Chris Bush and Bush himself finally made Stevens make a save as he was forced to tip over the centre halves header from a Willmott free kick.
It was a long ball from the back that brought about City’s best chance when Jeffers latched onto a long punt by Fitzsimons. Stevens backed off knowing he wasn’t making it but Jeffers’ header was gathered one handed by the retreating Stevens.
The Oxford goalkeeper though wasn’t so lucky the next time as the Clarets finally broke the deadlock after half an hour. Another long ball tempted Stevens off his line only for him to be beating by Mullings. Mullings’ touch took him wide but he composed himself to smash home the opener.
Chelmsford would go on to really stamp home their advantage as just over 10 minutes later they doubled their lead through Jeffers after he latched onto an Anthony Church header. Jeffers out-muscling his man to get into a shooting position seeing his shot squirm underneath Stevens to make it 2-0.
The score-line didn’t flatter the Clarets at all and they almost made it three late on as a free kick from Robbie Willmott was headed against the face of the post by Chris Bush and Jeffers came close to getting his second as his flicked header went marginally wide.
Stringer’s side kept up the pressure in the second half winning an early corner which Mullings will feel he should have done better with, heading over from eight yards out when unmarked.
Mullings was at the centre of everything the Clarets did in the attacking third, brushing off his marker to get another sight on goal which was deflected wide for a corner. From the resulting corner he failed to get a good connection on his header from three yards out seeing it go wide.
The striker then found himself clean through on goal on the counter attack only to see his effort just kept out by the feet of Stevens before Robbie Cundy got back to prevent Jeffers from tapping in the rebound.
Chelmsford City hit the woodwork for a second time in the game when Walsh’s header from a Willmott cross came crashing off the face of the crossbar, before Willmott picked out Luke Daley – who had been introduced from the subs bench – only for the winger to slice his shot over.
Daley almost wrapped up the victory again late on as he was picked out by Willmott once more only for his shot to be blocked and then desperately cleared by Freddie Grant.
Oxford were left to fight for scraps and their best chance came when the ball bounced kindly into the path of Bonafacio Neto but Walsh got back bravely to block the substitute’s attempt.
Liam Enver-Marum had a chance in injury time to reduce the deficit after Fitzsimons was adjudged to handle outside the area. The former Basingstoke front man went for placement over power but failed to find the target.
1. Ross Fitzsimons
2. Ashley Miller
3. Daniel Blanchett
4. Josh Rees
5. Chris Bush
6. Phillip Walsh
7. Robbie Willmott
8. Anthony Church (C)
9. Shamir Mullings
10. Shaun Jeffers
11. Bagasan Graham
12. Corby Moore
14. Billy Bricknell (On for Shamir Mullings 72’)
15. Adam Bailey-Dennis (On for Chris Bush 78’)
16. Luke Daley (On for Bagasan Graham 78’)
17. Joe Welch
1. Jack Stevens
2. Shaun MacAuley
3. Freddie Grant
4. Godfrey Poku
5. Eddie Odhiambo
6. Robbie Cundy
7. Louis Soares
8. Reece Fleet
9. Conor McDonagh
10. Scott Davies
11. Kynan Isaac
12. Bonafacio Neto (On for Eddie Odhiambo 64’)
14. Martin Ofosu (On for Kynan Isaac 57’)
15. Liam Enver-Marum (On for Connor McDonagh 57’)
16. Tom Winters
Chelmsford City: Shamir Mullings 30’, Shaun Jeffers 41’
Chelmsford City: Josh Rees (Foul 82’), Ross Fitzsimons (Handball 89'), Daniel Blanchett (Kicking the ball away 90+2')
Oxford City: Reece Fleet (Foul – 34’)
Referee: Elliot Kaye
Assistant Referees: Del Sotimirin & Craig Pullen
City Man of the Match: Robbie Willmott