At the start of the day, resuming on 358-7 in reply to Zimbabwe's XI 350-7, Mohammad Nabi scored a brilliant 102 as Afghanistan was dismissed for 427 all out. Timycen Maruma was the pick of Zimbabwe's bowlers as the 21-year-old off-spinner took 6-106.
Although it was 117-5 at tea, Tatenda Taibu's century led Zimbabwe XI's fightback in the final session of the day. At the close, the home team had moved on to 269-6, some 196 runs ahead, but had just lost Taibu for 120, a knock that lasted 195 balls and included 16 fours.
Meanwhile in Aberdeen, Scotland just managed to secure the six points on offer for an innings lead as Qasim Sheikh almost single-handedly dragged his side over the line.
The 24-year-old Glaswegian was the only Scotland player to make it past 30 and he was left unbeaten on exactly 100 as Ireland left-arm slow bowler Regan West took a magnificent seven wickets at the other end.
With Kyle McCallan chipping in with two scalps of his own, it was definitely a day for the slow bowlers but Qasim's priceless innings made sure Scotland reached 208 all out, a lead of just six runs.
In a thrilling conclusion to the first innings, Ireland pushed for the final wickets as the Scots looked to pass its total of 202 and bag the six points on offer. And at 196-7, that job seemed like a foregone conclusion but a quick wicket each for West and McCallan stunned Scotland to 199-9 and made for some tense moments in the Scotland camp.
But Sheikh did the business and then just had enough time to raise his bat for a fine century before number 11 Alasdair Evans was out, caught and bowled by West to complete the innings.
Ireland's second innings had begun well and, not long after the tea interval, it had moved on to 38-0 with Jeremy Bray and captain William Porterfield at the crease as the defending champion looks to set the host as high a target as possible.