Durham 259 and 89 for 1 (Stoneman 50) lead Middlesex 196 by 152 runs

Durham think so highly of Mark Stoneman that allowing him the time to find consistent form at the top of their batting line-up has always been considered worth the wait, even though there have been long periods of frustration to endure since the elegant left-hander made his debut in 2007.

He recorded his maiden first-class century in the same season, yet it took him four years to make his second and another 15 months had elapsed before his third. Several times he appeared to have made a breakthrough, only for another lean period to follow.

This season, however, the signs are that he may at last have found a way to sustain his form. His place in the side firmly established following the retirement of Michael di Venuto, Stoneman has settled into probably the most productive sequence of scores he has enjoyed so far.

In the last four matches, he has passed fifty five times, beginning with a century against Yorkshire, in a losing cause, before playing a key role in two successful run chases against Nottinghamshire and Surrey, making half-centuries in both innings in the latter of those games.

His 50 in this match might have been the basis of something more substantial had he not been seemingly cut off in his prime by an lbw decision that surprised even the bowler, James Harris, who stifled his appeal in the belief that the ball was missing leg stump only for umpire George Sharp to raise his finger anyway. Stoneman did not make an issue of the dismissal, although having assumed he was not out he had to ask for confirmation before walking off.

His was the only wicket to fall on a day restricted by bad weather to just 18 overs. Durham were the more frustrated team, having hoped that a 100-run lead overnight might be the platform from which they could have built an impregnable advantage and still have ample time to bowl out Middlesex for a second time.

In the event, they added only 52, but with a vastly improved forecast for the final day, they will still hope to press home their advantage. It will require runs to come at a brisk tempo in the morning and for captain Paul Collingwood to make a shrewd declaration if Graham Onions and company are to have enough offers to inflict the necessary damage but Stoneman believes Collingwood will want to make a game of it, even against opponents who may turn out to be title rivals.

"Ultimately you have to look at how many points you can get for yourself and not worry too much about what the opposition might be getting," he said. "If you win as many games as you can against all-comers then by the end of the year you will be in the right position, hopefully."