Xavier Vidal faces a lengthy lay-off after being carried off with a serious knee injury.
The 23-year-old Oaks midfielder, making only his second league start, after joining the club last month, opened his account with a spectacular first half strike, before suffering a dislocated knee with 18 minutes left.
Vidal was hurt in a challenge for the ball on the halfway line, but had the knee re-set, before visiting hospital on his way home.
The incident took the gloss off Oaks’ second successive away win and third of the season.
They recovered from a difficult opening half hour to lead 2-1 at half time with goals by William Johnson-Cole and Vidal.
Kenny Pogue added a third nine minutes after the break, before the blow of losing Vidal who could be out for several weeks.
Eddie Dsane pulled one back with four minutes left, setting up a lively finish with Oaks surviving some anxious moments as the clock ticked into stoppage-time.
Defender Tom Ripley produced one great last-ditch challenge, and then picked up a yellow card - his sixth of the season, felling a home player on the edge of the box.
However Dsane ballooned the resulting free-kick over the bar.
Leafe included two former Oaks players, former skipper Corey Holder and Harrison Carnegie against their old club.
Carnegie missed an early chance, taking one touch too many inside the area, after rounding Ben Bridle-Card, allowing Greg Benbow to clear.
Leafe missed two more chances before Scott Day put them in front after 17 minutes.
Oaks failed to defend a throw-in and Day beat Bridle-Card with a low finish.
He then tipped Dan Hector’s effort over the bar, before Oaks levelled.
The keeper who had a spell at Leafe a couple of seasons ago, launched a long clearance downfield, Pogue and skipper Frankie Sawyer combined well to put Johnson-Cole to score inside the far post - his fourth of the season.
Vidal got the second six minutes later. Alec Fiddis and Sawyer created the chance for him, before producing a 20-yard effort which dipped under the bar.
Fiddis went close again two minutes later, before Carnegie’s 30-yard strike hit the angle of bar and post four minutes before the break. It was his last contribution as he was substituted at half-time due to illness.
Pogue got the third- his second in two games - following up to score after Fiddis’ shot bounced off the bar.
Vidal’s injury looked a bad one, with the game held up for several minutes while he received.
Oaks conceded the late second following another quickly taken throw - Dsane scoring with an angled finish four minutes from time, but Oaks held on.