After having been in fourth for several weeks, the U's elevated themselves into third place in the League One table, with a crucial win away at Yeovil.
Kayode Odejayi's ninth goal of the season condemned the Glovers to only their fourth home defeat to date and pushed the U's closer to the top two in the division.
With Leeds slipping up against Walsall, the gap to second is now just three points - and first placed Norwich are only seven ahead of Aidy Boothroyd's men.
Two home games await as the U's look to continue their push for promotion.
For the game against Terry Skiverton's side, U's boss Aidy Boothroyd stuck with the same eleven that started at Stockport County on Saturday.
Ashley Vincent made the trip to the South West with the squad and looked close to a return as he went through a vigorous pre match work out with fitness coach Dave Carolan.
There was a change on the U's bench though, as David Fox replaced Paul Reid amongst the substitutes.
Skiverton made one change from the Yeovil team that drew 0-0 against Gillingham on Saturday, with Davies coming in for Mason. The hosts were sitting in fourteenth place prior to the game, ten places below the U's, who could move up to third with a victory in Somerset.
The first chance of the game came for the hosts, as Matt Heath was harshly adjudged to have committed a foul on the edge of the box. The free kick went safely over the bar though and it was the U's who had the next opportunity, again from a deadball situation.
David Prutton put his free kick into the danger area and after the ball dropped, John-Joe O'Toole had his shot saved by McCarthy.
Ben Williams was in action in the seventeenth minute, saving from Welsh before the play went back up the other end and the U's had a couple of efforts that went close.
First, Prutton's snapshot took McCarthy by surprise but went narrowly wide and then Kayode Odejayi hit the crossbar after latching onto a Wordsworth cross. The hosts lost Stam to injury following Odejayi's shot but it was the U's defence that had the next scare.
Skipper Magnus Okuonghae should have cleared but tried to play a short ball to White. It evaded White, who then slipped trying to reach it and Williams had to come to the rescue with a great save, before the ball was eventually cleared.
The U's then profited from a Yeovil defensive mistake, taking the lead through Odejayi. Wordsworth latched onto an awful clearance, found Platt and the first time lay off left Odejayi to firmly sidefoot his shot into the bottom corner.
The goal came in the thirty seventh minute and the last eight minutes of the half were played out mostly in the middle third of the pitch.
The U's went in at half time ahead by a single goal but Aidy Boothroyd would have been asking his players for a bit more concentration when defending and a bit more care on the ball.
And the U's did defend better in the second period, restricting the hosts to sporadic attacks. There wasn't too much action in the other penalty area either but the first two efforts both fell to Prutton.
His first time volley was straight at McCarthy but just before that, he took too long to set himself for a shot and a brilliant tackle denied him.
On the hour, Bowditch shot over when well placed and then Jones shot wide from a similar position.
Sub Steven Gillespie had a shot saved and the final action saw a free kick hit the side netting, with a number of home fans thinking their side had equalised.
It wasn't a classic but the U's gained three valuable points from a hard earned performance.
U's: Williams, White, Okuonghae, Heath, Tierney, Prutton, Izzet, O'Toole, Wordsworth, Platt, Odejayi.
Subs: Cousins, Ifil, Batth, Fox, Henderson, Elito, Gillespie.