Tom Lammonby scored a superb century and carried his bat to tip the scales in Somerset’s favour on the third day of their Bob Willis Trophy encounter with Worcestershire at Blackfinch New Road.

The 20-year-old opener hit an unbeaten 107 out of 193 all out and was largely responsible for Somerset being able to set a formidable 245 target on a wicket still offering encouragement to the seamers.

England paceman Lewis Gregory then picked up the key wickets of openers Daryl Mitchell and Jake Libby – two of the top five run-scorers in the competition – as Worcestershire reached 58 for two before bad light ended play early.

Lammonby became the youngest Somerset player to remain undefeated through an entire innings – surpassing Arthur ‘Dudley’ Rippon in 1914.

He concentrated initially on blunting the Worcestershire attack with some solid defence and accumulated only 23 runs from the first 104 deliveries he faced.

But the former England Under-19 player gradually flourished and played with increasing aggression as he required only another 101 balls to reach three figures.

Lammonby reached his hundred with one of three sixes – over long-on off spinner Brett D’Oliveira – and he also struck 12 fours.

His debut ton came in the previous match against Gloucestershire at Taunton but this was a far more significant contribution in the context of a potential Lord’s final spot being at stake for the winners of this game.

The Worcestershire seamers regularly picked up wickets and at 82 for six the Somerset lead was only 133 shortly before lunch.

But Lammonby received crucial support from the Somerset lower-order in posting a challenging target.

Somerset had resumed on 16 for one and found it hard work with Worcestershire skipper Joe Leach setting the tone by having Tom Abell caught behind from the fifth ball of the day.

The opening 45 minutes produced only four singles before Ed Barnard made a double breakthrough.

George Bartlett was trapped lbw and Eddie Byrom fell in the same manner after aiming a shot through mid-wicket.

Lammonby greeted D’Oliveira’s introduction with a huge six over mid-wicket but the leg-spinner persevered and Steve Davies paid the price for attempting an extravagant hit and was bowled.

It became two wickets in two overs for D’Oliveira as Craig Overton played back and saw his stumps rearranged.

Lewis Gregory (17) and Josh Davey (21) provided staunch support to Lammonnby after lunch during partnerships of 39 and 54 respectively

Gregory eventually perished to a fine catch by Libby running back from cover off Dillon Pennington.

After Lammonby reached three figures, Davey picked up three boundaries in the same over.

Another superb catch – this time by sub fielder Josh Dell at mid-wicket – brought about Davey’s downfall off Barnard.

The innings was quickly wrapped up with Jack Leach lbw to Barnard and Jack Brooks caught behind off Pennington. Barnard finished with four for 25 from 17 overs.

Gregory made the first breakthrough of the Worcestershire reply when Mitchell was bowled by a delivery which came back and kept low.

Libby, the competition’s leading run-scorer, was only two runs short of 500 when he was bowled off the inside edge by Gregory for 23.

Tom Fell and Jack Haynes added an unbroken 28 before play came to a halt 12 overs early.