Mansfield Town slipped to their third home defeat in Sky Bet League Two this season, as they went down 3-1 to Oxford United at One Call Stadium.
On a miserable afternoon for the Stags, the promotion-chasing visitors went ahead when Sean Rigg slotted home from close-range after just 12 minutes.
Midfielder Jamie McGuire was then sent-off on 22 minutes, following a strong challenge on Danny Rose, midway inside the U’s half.
Lee Stevenson hauled the Stags level on the stroke of half-time, when he hit a thunderous low volley through a crowded area and into the bottom corner.
However, James Constable quickly re-established the U’s lead, by bagging his 100th goal for the club in the eighth minute of first half stoppage-time.
The visitors sealed maximum points when Ryan Williams capped off a fine individual display, by slotting home a fine low cross by Rigg, midway through the second half.
Stags’ boss Paul Cox included frontman Jake Speight in his starting line-up, who was recalled from Alfreton Town just a few hours prior to the match.
On a bright but cool afternoon in North Nottinghamshire, it was the hosts who got proceedings underway, and attacked towards the Quarry Lane End in the first half.
On four minutes, the Stags created their first chance when Sam Clucas’ 25-yard snap-shot was deflected wide by U’s skipper Johnny Mullins.
However, James Jennings was unable to cause any danger from the resulting corner, which was well-claimed by Oxford keeper Ryan Clarke at his near-post.
The Stags nearly went ahead after nine minutes when Stevenson’s bullet-header from another near-post corner by Jennings, was superbly palmed away by Clarke.
As the Oxford defence scrambled to get the ball away, Danny Rose caught McGuire on the head, right on the edge of the area, which resulted in Mansfield being awarded a free-kick.
Junior Daniel’s low resulting set-piece strike took a wild deflection off Mullins and spun narrowly wide of the target, to give Cox’s side their second corner in as many minutes.
Nevertheless, Clarke showed good hands in claiming the subsequent corner by Jennings.
The Stags were then left to rue their misfortune in front of goal, as the visitors took a lead, somewhat against the run of play, on 12 minutes.
Rose showed quick-feet as he fended off a challenge from Jennings deep on the right flank, before cutting inside and unleashing a low drive towards goal.
Stags’ keeper Alan Marriott was only able to parry Rose’s effort towards an unmarked Rigg, who gratefully poked the ball into an empty net from just a few yards.
Matters then went from bad to worse for Mansfield on 22 minutes, when McGuire was shown a straight red card for a tough challenge on Rose, midway inside the U’s half.
Both Michael Raynes and Speight were booked by referee Charles Breakspear in the resulting melee, as the Stags task of earning something from the game grew.
Oxford dictated play in the immediate few minutes after McGuire’s dismissal, but neither Ryan Williams nor Asa Hall could find the target with speculative long-range attempts.
On the half-hour mark, Jennings saw another vicious in-swinging corner beaten away by Clarke, before there was a lengthy stoppage in play as John Dempster received treatment for a head injury.
Oxford then almost doubled their lead in a slick move when David Hunt’s free-kick towards the far-post from the right channel, was headed over by Mullins.
The Stags’ Stevenson was cautioned for a foul on Dave Kitson on 37 minutes and the U’s went close again on the brink of added time at the end of the first period.
Kitson and Williams combined on the right-wing, with the latter delivering a piercing ball into the area, which was eventually struck wide by Kitson.
For various reasons, there were eight minutes of added time at the end of the first period, during which the Stags forced a surprise equaliser.
Jennings’ left-wing cross was only partially-cleared by a stretched Oxford backline, following Dempster’s flick on, towards the edge of the area.
Stevenson picked up the loose ball and rifled a thunderous first-time volley through a crowded area and beyond the desperate dive of U’s keeper Clarke.
However, the Stags’ joy was short-lived as Oxford established a 2-1 lead at half-time, by finding the target in the eighth minute of first half stoppage-time.
Williams broke down the left flank, following a clever reverse-pass by Kitson, and poked a low ball into the area, which found Constable.
Marriott had little chance as the Oxford striker stabbed a low shot goalwards, which ricocheted off the post and into the net, sending the travelling fans into celebration.
The U’s then enjoyed a flurry of opportunities in quick succession shortly after the re-start, as they attempted to open up a two-goal advantage.
Constable twice headed wide from right-sided crosses by Kitson, whilst Williams also came close, having linked up with Constable.
Speight enjoyed a rare chance for Mansfield on 52 minutes as he raced onto a long ball over the top, but saw his powerful strike tipped over by a full-stretch Clarke.
Constable then enjoyed two efforts in quick succession as Oxford lurked dangerously with intent.
The Stags’ custodian tipped over a well-driven strike by the U’s talisman on 55 minutes, before he headed just wide from the subsequent left-sided corner.
Mansfield had another glimmer of hope close to the hour mark, when Beevers’ inviting left-wing delivery reached Dempster on the edge of the six-yard box.
His stab-shot attempt seemed dangerous, but Clarke was eventually able to scoop the ball into his arms, much to the relief of the Oxford defence.
By this stage, the home side were enjoying a promising spell of pressure, and they were unfortunate not to level for the second time on 63 minutes.
Oxford keeper Clarke and Daniel both raced to connect with a long ball forward by Jennings, and after meeting on the edge of the area, the ball span towards Clucas.
The youngster advanced with the ball into the area, rounding a grounded Clarke in the process, but due to being forced wide, could only screw a ball across the face of goal.
To compound matters, any hopes that Mansfield may have harboured about a comeback were dashed on 66 minutes, when Williams fired Oxford into a 3-1 lead.
Rigg, who scored the visitors’ first goal, drilled a superb low cross through the area from the inside-right, which was gratefully tucked away by Williams.
Nevertheless, the Stags showed plenty of grit and endeavour as they tried to force their way back into the game, with Dempster having a header saved by Clarke.
Following a good spell of possession, Clucas also whistled a 20-yard drive just over the woodwork on 75 minutes, though Oxford still looked comfortable.
The U’s pressed forward for a fourth goal in the closing stages, and almost found it when Rose flashed an effort just over the target.
Nevertheless, the match ended with the U’s emerging as deserved 3-1 winners – a victory which moves them to the top of the Sky Bet League Two table.
Attendance: 3,831 (769 away supporters).