Glamorgan 149 (Brook 3-13, Patterson 3-27) and 108 for 3 (Carlson 44*, Lloyd 40*) lead Yorkshire 230 (Root 99, Patterson 47*, Neser 5-39) by 28 runs

Joe Root moved inexorably towards his hundred with the precision of a ticking clock. An old-time image for an old-time innings. The world could do much as it pleased, nothing would change his tempo. Then, on 99, the clock stopped.

Root has 31 first-class hundreds, but only eight of them have come for Yorkshire. Even as a feted international player, one who bears an onerous responsibility as England's Test captain, his desire to succeed for his county remains implanted. He would surely yearn for more.

Medium-pacer Dan Douthwaite, who seamed the ball back sharply between bat and pad, was the bowler who stopped time. What's more, Douthwaite revealed, his teammate, Kiran Carlson, predicted it.

"It was weird how it happened," Douthwaite said. "Kiran Carlson stood at mid-off two balls before and said I was going to get him out trying to dab it down to third man and he would chop it on to the stumps and he did. I was telling him at the time to go away and let me focus on my bowling. That is the first time I have had someone predict a wicket and it has actually happened."

If Root didn't quite manage the century that had seemed inevitable, he looked in good trim ahead of the New Zealand Test series. His superbly controlled innings gave Yorkshire a chance of victory. That's if you don't believe in weather forecasts - Sunday's analysis suggests that these sides will be collecting draw points.

England's IPL contingent have spent much of the past fortnight in quarantine while the likes of Root have benefited from an extensive programme of Championship cricket, albeit played in empty stadiums and in largely cheerless conditions. It has not been a cakewalk. Remove his century against Kent at Canterbury and he had made 114 runs in seven innings. That rediscovered rhythm had been hard-won.

That Root's success has been far from automatic illustrates that bowlers have held sway and also points to the difficulties that even the most driven world-class player encounters when the prestige of a fixture diminishes and the pressure relents. Nevertheless, it also tells that this season's Conference structure has not been a succession of mismatches that many anticipated. It is a format that is gaining popularity and makes the structure for 2022 a debate still to be won and lost.

Glamorgan, down 81 on first innings, and seeded fifth out of six in Group One, might have capitulated when the Australian, Marnus Labuschagne, was bowled for a duck in an awkward 26-over finish to the day, but David Lloyd and Carlson played with typical freedom in slightly easing conditions in giving them a lead of 27 runs with seven wickets remaining at the close. Carlson's batting approach does not suffer from modesty and, with his 23rd birthday hours away, he looked to be a player worth keeping an eye on.

Not that Root defied Glamorgan single-handedly in giving Yorkshire that 81-run lead. At 111 for 8, they were imperilled, still 39 behind in seamer-friendly conditions. For a top-order batsman, eight-down often demands a rethink. Root observed his captain, Steven Patterson, and recognised a mulishness that demanded respect. Between them, another 118 were added in 33 overs. The match shifted.

Root was accomplished, his innings an exercise in precision. Patterson existed on defiance and an occasional square cut that he delivered with a flourish. He was far from rhythmic: if he had been a ticking clock, nobody would have had a clue what time it was. He survived a tough chance to backward point before he had scored, took several blows to the body and stubbornly insisted on his right to stick around. But his commitment was exemplary and he also deserved - and missed - his own statistical landmark, a fifth first-class 50, when he was left stranded on 47.

Glamorgan's tactics were strange. The Australian, Michael Neser, who had 3 for 15 overnight, soon had a five-for, including the frisky debutant wicketkeeper, Harry Duke, who was treated to a bouncer first ball, took it on, and spliced a catch to square leg. (First-ball duck or not, we will hear more of Duke). But Neser only bowled eight overs all day and must surely have a niggle.

Michael Hogan, the other senior strike bowler, spent the day bowling into the wind. The next bouncer of note to the ninth-wicket pair was delivered by Labuschagne, a part-time legspinner, and it disappeared for four byes. Andrew Salter had a spell of off-spin more out of respect than logic. Like Dom Bess, an England offspinner in Yorkshire's side, he would have been better rendered idle.

Root survived a strong leg-before appeal from Timm van der Gugten on 87, but otherwise picked out singles at will. His late cut to third man - the one where he might be picking his own pocket - would have had Fagin singing with delight. But, with Root on 99, Douthwaite cut Patterson in half with a big break-back that went for four byes. The warning was there. Root did not play the shot, but he might have anticipated it. His stumps were disturbed and Douthwaite gestured in triumph towards Carlson at mid off as if he had known the plan would work all along.