They host Forest Green Rovers at the weekend knowing that one more point will do the job, though they would need to lose and Port Vale, Swindon Town and Sutton United all win to deny Stags a top seven finish.
Automatic promotion is still possible but highly unlikely as it would rely on Bristol Rovers failing to beat Scunthorpe United at home.
The play-offs will start on Saturday 14th May, with seventh hosting fourth, following by sixth hosting fifth the next day with a noon kick off.
The all important second legs take place the following midweek with fourth v seventh on 18th May (7.45pm) and fifth v sixth on 19th May (7.45pm)
The final at Wembley is on 28th May.
Sutton and Tranmere currently sit outside the play-offs with the Londoners travelling to Harrogate on the final day and Rovers heading to Leyton Orient.
Swindon have a testing trip to Walsall to see off to confirm their play-off place while Port Vale have the biggest task of all with an away date at leaders Exeter City.
Northampton Town can seal promotion with a win at Barrow – a win they will have to get with Bristol Rovers facing as near of a gimme as you can get in League Two right now.