|Specsavers County Championship Division One, Emirates Old Trafford, day two|
|Somerset 553-8 dec: Trego 154, Abell 135, Davies 86, Trescothick 60; Bailey 5-111|
|Lancashire 138-2: Hameed 56, Jones 34|
|Lancashire (2 pts) trail Somerset (4 pts) by 415 runs|
Somerset centurion Peter Trego made a career-best 154 as Somerset's eighth-wicket county partnership record was broken for the second time in six days.
Wicketkeeper Ryan Davies made 86, also a career-best, in a stand of 236.
That broke the previous record of 217, set only last week by Roelof van der Merwe and Craig Overton.
Somerset batted on after Davies had gone before declaring on 553-8, to which Lancashire have replied with 138-2, of which Haseeb Hameed made 56.
In partnership with 20-year-old Rob Jones, who was making only his second Championship appearance, 19-year-old Hameed went past 50 for the 11th time this summer.
Together they forged the youngest Lancashire opening partnership in living memory, putting on 87 before Hameed was caught behind off Tim Groenewald.
Jones, having played a straight drive, was then run out by Groenewald for 34 after a lightning fast pick-up and throw from the bowler.
By the close, Alviro Petersen (25 not out) and Liam Livingstone (20 not out) had put on 42 together, leaving the hosts needing a further 261 on day three to avoid the follow-on.
Lancashire batsman Rob Jones told BBC Radio Manchester:
"It's turned out to be a good day for us. It's not the most enticing wicket to bowl on but they batted well and ground us down.
"But we fought back. You just have to break it down session by session, ball by ball.
"Opening was a good opportunity for me. I was a bit unlucky to get out but it was a great piece of fielding.
"It's been brilliant in the first team but there is more pressure. If you get an opportunity, you have to take it but it's great that Ashley Giles backs us and gives us a go."
Somerset all-rounder Peter Trego told BBC Radio Somerset:
"It was remarkable to break the record on the back of a 20-year-old eighth-wicket record being broken against Hampshire.
"It was great to see how Ryan's developed. He played a really mature innings and was a good foil for myself. We had a really good time out there.
"If you could bottle the way I felt on Wednesday evening, you'd get a lot of runs. I didn't go out there trying to chase boundaries, I just tried to watch the ball. I don't think those shots were rash, I just played really nicely.
"I was pleased that my batting game has come together and I certainly feel that there is a lot more to come. I've left it a little late in my career but I'm still fit enough to score a lot more runs for Somerset."