Lancashire 199 for 5 (Allen 66, Jennings 56) beat Durham 193 for 5 (Dickson 53, Bedingham 50) by six runs

Lancashire do not have blissful memories of this fixture. Three years ago they failed to score six off the final over when they had four wickets in hand. That defeat led to one or two frank exchanges in the dressing room and the departure of Jordan Clark to Surrey, albeit that had been possible for a while. Then last year their batsmen were swept aside like shingle in a perigean spring tide by an ecstatic Matty Potts.

And for much of this magnificent and vital contest it looked as though Durham were up to their quite recent tricks yet again. Chasing 200 for victory, a total they had never scored to win a T20 match, Cameron Bancroft's men approached their task with very typical courage. David Bedingham was largely responsible for his side taking 78 runs off their Powerplay overs and even after he had been caught at short third man for 50 by the substitute fielder Jack Blatherwick off Tom Hartley, the visitors' pursuit was maintained on a very good batting pitch by Sean Dickson. With two overs to be bowled 26 runs were still needed but Luke Wood had Dickson caught at long-off by Steven Croft for 53 and Danny Lamb kept his no doubt febrile nerve to bowl a series of yorkers when Durham needed 15 off the final six balls. Lancashire won by half a dozen runs but the visitors came closer than that and as so often in such contests the emotional polarities at the end of the match were revealing.

For this game mattered a lot. The Vitality Blast season has moved from simple entertainment to dread consequence. Most analyses of this evening's programme began with "if" and ended in a labyrinth of knotted possibilities. Simplicity was rarer than Prime Ministerial truth. And even now Lancashire have secured the victory, things are not completely clear. True, Durham now have no chance of reaching the quarter-finals, a fate they hardly deserve, but Lancashire's place in the last eight rests on - wouldn't you guess it? - the game against Yorkshire. Win that and they can look forward to an away quarter-final. Lose and their fate depends on Northants and Leicestershire defeating Birmingham and Worcestershire on Sunday.

The most straightforward way of dealing with affairs - and also the most pleasing from head coach Glen Chapple's point of view - would be simply to beat Yorkshire, and that task will be facilitated if Finn Allen and Keaton Jennings bat as they did in the opening overs against Durham. As though carrying scarred, second-hand recollections of recent games against these opponents, Lancashire's openers began by dismantling Bancroft's attack and then demolished it almost completely. The first four overs of the innings brought 45 runs, the Powerplay 75. Spin or seam, left hand or right, it made no difference. Allen hit three sixes in reaching his fifty off 21 balls, equalling the second quickest in the county's short-form history. He and Jennings put on 101 in eight overs before the New Zealander holed out to Scott Borthwick's leg spin for 66, Carse taking the catch at long-off. Two overs later Jennings top-edged the same bowler to Paul van Meekeren at short fine leg and departed for 43.

The run-scoring slackened in the third quarter of the innings and perhaps it could scarcely have done otherwise. Alex Davies and Dane Vilas took stock to the extent that none of the overs between the ninth and fifteenth yielded ten or more runs. Then Davies whacked Trevaskis for a six and a four and Lancashire were off again. Well, at least Davies was. The endlessly combative batter reached his fifty off 36 balls in the 19th over but holed out to Borthwick off Potts at long-on for 56 four balls later and Lancashire finished on 199 for 5. Borthwick was the pick of the Durham bowlers and his 2 for 30 were the best figures. That is not always the way. Statistics sometimes wrong-foot performance in this game.

Similarly a side chasing a tall total can often fold up and subside. But that has never been Durham's way. Bedingham belted almost every bowler in the Powerplay and Dickson's approach to his task was epitomised when he whacked a straight six off Croft that smashed a window in the home dressing room and left an outraged Chapple standing arms akimbo on the balcony as if making the points that someone had got to pay for the damage and Lancashire are not made of windows.

So the T20 season comes down to the last weekend of group games. Lancashire can be encouraged that they have now won five of their six home games and tied the other. On the other side they would not be facing such a tense denouement to their campaign if they had more than just one win from seven matches on their travels. An incompetent philanderer could not have played away with less success.