SA have a very vulnerable middle order, and their best hope is ABDV sticking around long enough and not running out of partners now du Plessis has walked.
Six wickets tomorrow is by no means an easy task, but you have to reckon it'll be done inside two sessions.
Credit to Finn - who bowled superbly - and Bairstow for his batting. I felt the latter's missed stumping was a half chance, really, and it seems unfair he's being targeted for that mistake when there were plenty of easier ones put down by others during the first innings.
As for the former - what a player he is turning into. It didn't even seem possible that he'd make the tour, for Christ's sake, but he's rapidly becoming a key cog in the England machine. I'm chuffed for him. All his wickets came at key and crucial times today. He is an awkward, unorthodox presence in the England attack, but a vital one.