Ryan Gallagher scored a brace of tries as Bicester won 41-14 at Chipping Norton to maintain their BB&O Premier Division promotion push on Saturday.
Bicester will guarantee second place with a bonus-point victory over struggling Farnham Royal in their final match on Saturday, April 12.
No 8 Gallagher opened the scoring on six minutes, with centre Dan Spencer slotting the first of three conversions.
Wing Dave Aslett grabbed try No 2, but Chippy hit back to send centre Mark Barnes over, with fly half Darren De Bruyn converting.
Centre John Behan, wing Jezz Tanner, Gallagher and flanker Matt Dye went over to stretch the visitors’ advantage.
Chippy’s De Bruyn sprinted over from close range, with replacement James Blake converting.
Scrum half Mike Harris had the final say with Bices-ter’s seventh try.
Alchester, who are already safe from relegation, lost 14-3 at home to third-placed Thatcham in Southern Counties North.
The hosts’ only points came via a Tom Miles penalty.