The equation is simple. 33 runs will provide Bangladesh with a first Test Match victory over England, whilst two wickets will ensure the visitors cannot lose the two-game series.
England capitulate before a Kayes acceleration
England would have enjoyed the happier dressing room overnight but struggled to build upon their advantage as they added just twelve runs to their overnight total. It was to be the first time Bangladesh had taken all 20 wickets in a Test Match. Falling 30-40 runs short of their objective, the visitors were tasked with defending 285 in Chittagong.
On a degrading pitch, the hosts decided their best hope was to attack the English bowlers, in particular their trio of spinners. Though they lost opener Tamim Iqbal for just nine to Moeen Ali.
At the other end Imrul Kayes toiled away and was the main instigator of the counter-attack, blasting his way to 43 with six boundaries. He eventually fell to Adil Rashid as Bangladesh picked off 81 runs in the space of their opening two partnerships.
The dismissal of Kayes provided the platform for England to build upon as they took regular wickets. The aggressive and impressive old stager Gareth Batty picked up two and Moeen added another as Bangladesh fell to 140-5 and looked to be staring down the barrel.
The pendulum swings back and forth
Yet a patient partnership of 87 between Mushfiqur Rahim and Sabbir Rahman gave the hosts a real chance of creating history. Batty eventually dismissed Rahim for 39 off 166 balls and that provided the catalyst for the pendulum to swing in England's favour once more.
Three wickets for the loss of just eleven runs made the visitors favourites as Stuart Broad chipped in with the first two seam wickets of the innings. Yet England historically struggle to see off the tail and that was to be the case again. Number ten Taijul Islam dug in alongside Rahman who passed his half century, despite being dropped earlier on.
As bad light caused an abrupt end to an intriguing contest twelve minutes early, all the ingredients are prepared for an exhilarating finale on Monday. Although the whole day is available, it is likely the contest will be concluded within the first session as Bangladesh eye 33 runs to win and England two wickets.