Lancashire 140 (Jennings 56, Overton 4-32, Gregory 4-50) and 16 for 1 lead Somerset 146 (Bailey 4-36, Balderson 4-50) by 10 runs

Twenty-one wickets fell on the first day of the Vitality County Championship match at Emirates Old Trafford where title-chasing Somerset earned just a six-run first-innings lead over Lancashire, who probably need to win this game to avoid relegation.

Having opted to field, Somerset's quicker bowlers made good use of an olive-coloured pitch on the edge of the square to take four wickets in the first session. The first batter dismissed was Harry Singh, whose maiden Championship innings ended on 7 when he edged Overton to Tom Lammonby at third slip.

Four overs later, Josh Bohannon followed for just 4 when he was beaten by a fine ball from Overton and nicked a catch to wicketkeeper James Rew. Rocky Flintoff was bowled for 7 when he inside-edged an attempted off drive to a ball from Kacey Aldridge into his middle stump and the same bowler took his second wicket in similar fashion when Jennings's front-foot slash only diverted the ball into his stumps.

Three balls previously, Jennings had reached his fifty and three runs off the next delivery from Brett Randell saw him reach 1000 Championship runs for the season. However, his dismissal for 56 left Lancashire on 85 for 4 and Somerset might have been reflecting that things would have been even better for them had not Aldridge dropped Jennings at slip off Overton's first ball of the game.

Things declined rapidly for the home side early in the afternoon session as they lost their next four wickets for one run in 24 balls and their last six for 33 runs in less than an hour's cricket. Gregory dismissed four of the batters to finish with 4 for 50 and Overton picked up two more to return figures of 4 for 32 from 15 overs.

Despite losing Andy Umeed, caught by Jennings off Tom Bailey, to the first ball of their innings, Somerset added 58 runs in relatively untroubled fashion until they lost three wickets in 13 balls just before tea.

Archie Vaughan, who made 21, and Tom Kohler-Cadmore were both caught behind off Balderson and those dismissals sandwiched the departure of Lammonby, who pushed forward to Will Williams when he had made 36 and nicked a catch to George Bell at slip.

Things got no better for Somerset immediately after tea when Rew became the third batsman to be caught behind by Matty Hurst off Balderson and Rew's dismissal for 4 was quickly followed by that of Aldridge, who lost his off stump to Balderson when he had made a single, to leave Somerset on 83 for 6.

Gregory and Tom Abell inched their side towards Lancashire's total with a 34-run partnership for the seventh wicket but Bailey had Abell caught behind for 22 and then dismissed Overton and Randell, both leg before wicket, in the space of three deliveries, Overton falling to an outrageous slower ball.

Jack Leach then helped Gregory put on a priceless 25 for the last wicket before he was caught behind off Anderson Philip for 13, Hurst taking his fifth catch of the innings.

Five overs before the close, Jennings edged Gregory to Andy Umeed at slip and the day ended with Singh and nightwatchman Williams defending stoutly against the Somerset attack.