Millwall 0, Oxford United 3 (McAleny 6 & 8, Ruffels 71)

The Everton loanee moved on to ten goals for his spell with the U’s thanks to a pair of high-quality strikes in the opening ten minutes.

United were barely stretched before the break, but had to show plenty of defensive grit as the Lions pushed them back early in the second half.

Millwall could not find a breakthrough, though, and 19 minutes from time the visitors knocked the stuffing out of their hosts when Josh Ruffels headed in Chris Maguire’s corner.

The result moved the U’s up a place to ninth, agonisingly four points adrift of the play-off positions with one game remaining.

Remarkably given they have lost twice this week, Millwall clung on to sixth place as rivals Southend United and Rochdale slipped up elsewhere.

United’s teamsheet had many thinking Michael Appleton would change his side’s shape, but they remained 4-4-2.

Canice Carroll came in on the right side of midfield, while McAleny was switched to the left to make room for Chris Maguire to play up front with Marvin Johnson.

Christian Ribeiro returned at right back, as Phil Edwards, Joe Rothwell and Rob Hall dropped to the bench.

The Den had not seen an away win since December 10, but the visitors instantly made themselves at home.

From the kick-off they kept the ball for the opening minute and it did not take them much longer to race into a 2-0 lead.

United seemed to have men in space all over the pitch and McAleny provided the finishing touch twice in less than three minutes to stun Millwall.

The opening goal came at the end of some slick football.

Ribeiro, Johnson, Maguire and Ruffels were all involved to find McAleny 20 yards out, where he smashed a sweet half-volley into the far corner.

Millwall goalkeeper Jordan Archer was grasping at thin air again shortly afterwards.

Another move saw the hosts chasing shadows and John Lundstram spread the ball to find McAleny on the left corner of the penalty area. After controlling the ball stone dead, he cut inside to curl a shot into the net.

• Conor McAleny scores his second goal

It was took his tally for the loan spell at United into double figures – quite an achievement for a player who did not make his debut until February.

Millwall’s home fans were silenced as the assured visitors continued to enjoy the excellent playing surface at The Den.

By contrast, the travelling support divided their time between praising their side and chanting about Swindon Town slipping towards relegation.

United were playing without pressure, summed up by one moment just before the half-hour mark.

Receiving a bouncing ball, Carroll impudently flicked the ball over Tony Craig, who at 32 was 14 years his senior. The experienced Lions defender was bamboozled by the flash of skill and was booked for bringing down United’s No 35.

In Steve Morison and Lee Gregory the hosts had one of the division’s most effective front two partnerships, but they got little change out of a United back four who were strong and made good decisions.

The only moment of concern for Simon Eastwood came at an early corner where the goalkeeper appeared to be fouled, but with the referee seeing nothing wrong United were relieved to see Ruffels make a clearing header.

Chances to add a third goal before the break were in short supply, with Johnson wildly off target with a free-kick routine late in the half.

Millwall were booed off at the break and Craig was replaced by Shane Ferguson for the start of the second half.

To begin with little in the game changed and only an excellent defensive block kept out McAleny nine minutes into the second half after Maguire had got round the back.

But Millwall could not be so disjointed all afternoon and steadily they got a grip on the game.

Their big chance arrived on the hour, when a ball forward fell kindly for Aiden O’Brien. He only had Eastwood to beat, but the goalkeeper stood tall to make a crucial block.

Even so, the home fans were growing in confidence as their side went on to pin United back for ten minutes.

A succession of corners and free-kicks around the visitors’ box cranked up the pressure, but Eastwood’s goal was not breached.

And out of nothing, United sprung forward to land the sucker punch.

• Josh Ruffels makes it 3-0 with a header from Chris Maguire's 71st-minute corner

McAleny won a corner, from which Maguire delivered deep for Ruffels to nod in from five yards.

It deflated Millwall, who sat off their opponents, giving the away fans a chance to cheer every pass.

Morison fired a shot on to the roof of the net and nodded another half-chance wide, but the Lions looked a beaten side well before the final whistle.

While home fans flooded on to the pitch at the final whistle, they had little to celebrate as United's players sprinted off to celebrate the result.

Millwall (4-4-2): Archer, Romeo, Webster, Cooper, Craig (Ferguson HT), Wallace, Thompson, Williams, O’Brien (Worrall 78), Gregory, Morison.

Unused subs: King, Cummings, Martin, Butcher, Onyedinma.

Booked: Craig.

Oxford Utd (4-4-2): Eastwood, Ribeiro, Nelson, Raglan, Skarz, Carroll (Rothwell 77), Lundstram, Ruffels, McAleny, Maguire (Hemmings 85), Johnson (Hall 85).

Unused subs: Stevens, Long, Dunkley, Edwards.

Booked: None.

Referee: Dean Whitestone (Northamptonshire).

Attendance: 12,533.