Worcestershire 200 (Libby 58) and 58 for 2 need another 186 runs to beat Somerset 251 (Abell 59) and 193 (Lammonby 107*, Barnard 4-25)

Tom Lammonby's unbeaten century has given Somerset an excellent chance of making the final of the Bob Willis Trophy.

Lammonby, a 20-year-old who made his first-class debut in August, became the youngest man in Somerset's first-class history* to carry his bat in making 107 of Somerset's 193. Nobody else managed more than 21.

It was the first time a Somerset opener had carried their bat since Dean Elgar did so in Manchester in 2017. Lammonby also becomes just the second man who might be considered locally developed - he was born, to an Australian father, in Exeter - to do it for Somerset this century; his captain, Tom Abell, has done so twice. It was Lammonby's second century in successive first-class matches.

More importantly, Lammonby's chanceless innings shored up Somerset's position just as it appeared to be crumbling. There were times on the third morning when it appeared Worcestershire had clawed their way back into this game. At 82 for 6, for example, Somerset were just 133 ahead and in danger of letting their advantage slip.

But Lammonby's impressively calm head, his ability to play to the situation and go through the gears when required, his ability to concentrate for five hours and wear down Worcestershire's deserving attack left the hosts needing 245 to win. Against a Somerset attack which has not conceded more than 200 in the competition and on a surface that remains helpful to seamers, that is likely to prove a tall order.

In normal circumstances, Lammonby may have struggled to win an opportunity this year. Somerset were due to welcome Matthew Wade as their overseas player at the start of the season and Vernon Philander as a Kolpak registration. James Hildreth and Tom Banton might also be considered first-choice options, while Lammonby, a former England U19 player, has very little experience at the top of the order. Instead, he sees himself as a middle-order batsman who can contribute with the ball as a left-arm medium-pacer. He reckons he has opened, at club level, just three or four times previously.

But, the absence of most overseas and Kolpak players has provided opportunities for the likes of Lammonby. And in recording successive centuries, he may have gone some way towards filling the Marcus Trescothick-shaped void that has existed at the top of the Somerset order for a while.

As a left-handed Somerset opener, the comparisons with Trescothick are probably inevitable. But Lammonby perhaps has more in common with the likes of Alastair Cook or even Peter Roebuck (a right-hander, but a Somerset opener) than Trescothick. He is patient, compact and well-organised. He was, in general, happy to accumulate rather than dominate. And while there were few of the booming drives or dismissive cuts and pulls that characterised a typical Trescothick century, there were arguably fewer nervous moments outside off stump, too. In carrying his bat in a first-class game, he has already achieved something for Somerset that Trescothick did not.

Initially, he concentrated on survival. There were just four singles in the opening 45 minutes of the day and, after 104 balls of his innings, he had scored 23. But he had played straight, he had left well and he had still been able to put away anything overpitched or on his legs.

He seized on the introduction of Brett D'Oliveira's leg-spin as an opportunity for easier runs. The first two balls were taken for 10 - a sweep for four followed by a lofted drive over long-on for six - while an over in his second spell was plundered for 20. Lammonby brought up his century with his third six off D'Oliveira. In the context of this low-scoring match, it was agonisingly expensive for Worcestershire.

Batting looked a far more tricky proposition at the other end. Abell fell in the first over of the day, a perfect outswinger taking his the edge of his forward defensive prod, before George Bartlett and Eddie Byrom were both punished for playing across straight balls. Steve Davies' attempt to emulate Lammonby's aggression against D'Oliveira saw him miss a bit of a heave while Craig Overton, back when he should have been forward, was beaten by a googly.

But in Lewis Gregory and Josh Davey, Lammonby found some support. And with Josh Tongue only able to operate off a short run and at half pace due to a back injury, Worcestershire's support bowlers, notably D'Oliveira and the rapid but raw Dillon Pennington, proved expensive. The hosts' grip on the situation began to weaken as Lammonby's final 84 runs occupied only 116 balls and Somerset's last four wickets added 111 crucial runs. In the context of the match, it felt decisive.

Worcestershire's task looked no easier after the loss of both openers. Daryl Mitchell and Jake Libby are their side's highest run-scorers in the competition but were both bowled by Lewis Gregory: Mitchell punished for leaving a gap between bat and pad by one that drifted into him; Libby playing on via the inside edge after a somewhat footless drive at one which left him a little. The mountain they have to climb on the final day looms above the Malverns.

Lammonby has only visited Lord's once before - as a spectator at Somerset's Royal London Cup success last year - and has never played there. It will be a surprise if he is not making his maiden appearance there in a couple of weeks' time.

*The previous youngest was ADE 'Dudley' Rippon, in 1914.