Mick Newell, the Nottinghamshire director of cricket, had an idea some weeks ago that this match rather than the two to come against Warwickshire would be what defined his side's season. Regrettably for him, the way it is unfolding is cruelly proving the wisdom of his judgment.
Weakened by injuries and international call-ups, Nottinghamshire have been slipping backwards here since the end of the first session on day one, their prospects reduced first by the loss of the next two sessions to rain, then by letting Durham off the hook at 123 for 8 and next, most significantly, by the damage wreaked by a rampant Graham Onions.
Yesterday, they were pushed further into arrears as Durham built on a century from opening batsman Mark Stoneham to establish a platform which will allow Onions to bowl as aggressively as he likes on the final day, with every chance of dealing Nottinghamshire's title prospects perhaps terminal damage.
A half-century partnership between Paul Collingwood and Mark Wood in the final session seemed to make a Nottinghamshire win unlikely, at least.
Stoneman's record of converting half-centuries to centuries is not good. This was only his fourth success in a career so far spanning six seasons despite going past 50 some 19 times, yet here he reached both milestones with a confident touch, completing his half-century with his eighth boundary, driven through backward point off Luke Fletcher.
Then, when you wondered if he might become twitchy, he advanced from 90 to 103 in five shots against the left-arm spin of Graeme White, the last two of them boundaries.
Stoneman did not hang around for much longer. In a freakish end to the innings, he was dropped twice and dismissed leg before wicket in the space of four deliveries. Stoneman lacked substantial support, but Keaton Jennings contributed 31 in a second-wicket partnership of 74 with him, while the late stand by Collingwood and Wood chipped in enough to give Durham every chance of ending their concerns about relegation with a third straight win.
Nottinghamshire's bowlers tended to start strongly but lose momentum. The suspicion that they rely rather too heavily on Andre Adams, who is missing with a hamstring injury, is being borne out.
durham 194 & 301-7