South Africa A 283 and 29 for 4 (Overton 3-22) need another 383 runs to beat England Lions 386 and 308 for 6 dec (Stoneman 86, Jennings 71, Gubbins 63)
Scorecard
Three of the contenders for a possible Test call-up - Keaton Jennings, Mark Stoneman and Nick Gubbins - all made half-centuries as England Lions pressed for victory against South Africa A in the tour match at Canterbury.
Skipper Jennings and former Durham team-mate Stoneman passed 50 for the second time in the match before Middlesex's Gubbins sped the Lions toward a declaration with 63 off 65 balls.
England pulled out on 308 for 5 after scoring at nearly five an over on a slow pitch, leaving South Africa A with a target of 412 but they lost four wickets before the close, three of them to Somerset's Jamie Overton in successive overs.
Openers Adrian Markram and Heino Kuhn had put on 164 in the first innings but were parted with 8 on the board this time around when Essex's Jamie Porter defeated Markram's tentative defensive push. Overton then had Kuhn and Khaya Zondo caught behind and Theunis de Bruyn smartly held at fourth slip as South Africa A limped to 29 for 4 at stumps.
A fortnight after he made his career-best 197 for Surrey in the Specsavers County Championship, Stoneman continued his impressive form with 86. He was dropped on 20 and 33 but the left-hander played confidently on both sides of the wicket with 15 fours and a six off offspinner Dane Piedt.
Stoneman and Jennings came together after Haseeb Hameed had been dismissed cheaply for the second time in the match when he was squared up by Beuran Hendricks. The second-wicket pair put on 145 in 35 overs and Stoneman appeared to be cruising towards his fourth hundred of the season when he played on to Duanne Olivier after facing 129 balls in 163 minutes.
Having hit nine fours in 122 balls, Jennings, one of only three players in this week's squad who are in the party for the Lions game against South Africa next week, fell for 71 to a smart slip catch cutting against the spin of Piedt before left-hander Gubbins began England's acceleration after tea.
After Dan Lawrence had been caught behind off Hendricks, Gubbins and Ben Foakes, who made an unbeaten 127 in the first innings, added 69 in 7.4 overs with Foakes employing the slog-sweep against Piedt to good effect, twice clearing the midwicket boundary in the same over.
Gubbins wasn't afraid to employ the long handle either, depositing Hendricks over long-on for six. Foakes drove to cover after making 34 from 27 balls and England declared when Gubbins, who struck eight fours and a six, was out in similar fashion.
Earlier, South Africa A had been bowled out for 283 - a deficit of 103 - in their first innings after their last three wickets added 46.