Things could have been so different if, after just one minute, Abbey Nsubuga had made better contact on a ball headed on by debutant Chima Eberendu. His weak shot across goal was gathered comfortably by Smith in the home goal.
Slough’s bright start continued as Metcalfe had a volley blocked at the near post. The ball was worked to Barratt who hit a venomous strike across goal, but did not worry Smith. Lee Riddell also attempted a long range looping volley to catch Smith off his line, but the home keeper was quick to react and saved easily.
On 18 minutes, Dave Barratt fired in a powerful shot from the right, but Smith showed good hands and held the ball comfortably.
However, poor Slough defending led to the opening goal on 22 minutes. A shot was blocked by Daly, which looped up to Bell at the back post. Bell then cut inside two players and finished low to Barnard's left from eight yards to stun the Rebels after a decent start.
The Rebels seemed perturbed by this goal, and former Wycombe striker Jermaine McSporran latched onto a long ball through down the right wing and flashed a cross shot across the goal, but nobody could get the telling touch in the middle.
It was McSporran who made it 2-0 on 32 minutes. He latched onto an Alex Stewart header and touched the ball over an advancing Barnard. A tidy finish and one which caused Slough heads to drop further.
Two minutes before half time, Oxford added a third. Alex Stewart flicked a header on across goal and past a stranded Barnard to leave the Rebels chasing another heavy deficit.
The second half saw Slough create only a few half-chances, whilst defensive lapses were punished further by the free-scoring hosts.
Steve Daly had the first chance of the half, getting his head to a Michael Murphy corner to put the ball wide of goal.
Oxford broke down the right in the 56th minute and a low cross into the middle forced a great save from Barnard as Stewart fired at him from close range. Soon after, they broke again and carved apart the away defence only for substitute Anya to have his goal ruled out for offside.
City made it 4-0 on 65 minutes. The Rebels failed to deal with a corner kick and the ball was headed home at the far post by Gunn, with Barnard misjudging the flight of the ball.
Home goalkeeper Smith was shown a yellow card for a handball outside his box, however the resulting free kick was fired just over the bar by Lee Riddell, with Slough looking for a consolation.
The scoring was complete in the 82nd minute as left sided player Jon Gardner cut inside onto his right foot and hit a cracking shot past Barnard from fully 30 yards, with the Rebels’ keeper appearing to see the ball late.
Slough managed to create one good chance for a consolation, with the ball being worked to Barratt on the right hand side. His low cross into the middle was missed until Sakala arrived at the back post with the goal gaping. However, Smith was able to make a great save. The rebound fell to Thomas Attrell who blazed over.
Oxford City saw out the rest of the game comfortably to record a resounding win and move top of the league.
Oxford City Line up
1. Steve Smith, 2. James Saulsbury (c) (15. Mark Janes), 3. Stuart Cattell, 4. Andy Gunn, 5. Darren Pond, 6. Mark Avery, 7. Jon Gardner, 8. Liam Malone, 9. Jermaine McSporran (14. Ikechi Anya), 10. Alex Stewart (12. George Redknap), 11. Mark Bell. Subs not used: 16. Justin Merritt, 17. Lee Rendell.