LV COUNTY CHAMPIONSHIP DIVISION ONE, Headingley:
CLOSE OF PLAY, DAY THREE: Lancashire 416-9 dec, Yorkshire 199-8
(Lancashire 5 pts, Yorkshire 2 pts)
Smith's only previous first-class ton was against Durham UCCE in 2009
Tom Smith weighed in with a fine all-round performance as Lancashire set up a potential winning platform on day three in the Roses match at Headingley.
Smith hit an unbeaten 108, his first Championship century, as Lancashire declared on 416-9 before taking 4-46, also a season's best, with the ball.
Despite Adil Rashid's 65, that left Yorkshire on 199-8 at the close.
And, going into the final day, the Tykes still need another 68 to avoid the follow-on, with two wickets left.
After Lancashire began the third day on 272-5, one of the rare moments of Yorkshire cheer came from Steven Patterson's second ball of the morning when he trapped Luke Sutton lbw to bring the home side a second bowling bonus point.
Lancashire's bid to secure a fourth batting point ended when Sajid Mahmood was lbw to Shahzad in the 110th over but the innings was far from over at 337-8 as Kyle Hogg joined Smith in a ninth-wicket stand of 79.
Smith, 46 overnight, overtook his previous Championship best of 95 and was stuck on 99 for a while before he seized upon a full toss from Sayers and smacked it to the mid-wicket boundary to go to his century off 158 balls with 10 fours.
Hogg played a full part in the alliance and his spirited innings of 37 lasted until the final over before lunch when he was stumped by Jonny Bairstow off Rashid to bring about the declaration.
Things immediately went badly awry for Yorkshire when they began their reply after lunch.
Adam Lyth deflected visiting skipper Glen Chapple's second ball of the innings into his stumps to bring an early end to his outside chance of rattling up the 147 he required to reach the 1,000 first-class runs before the end of May.
Chapple struck again with his seventh delivery which trapped Anthony McGrath lbw. But Jacques Rudolph counter-attacked with five boundaries in his first 21 runs before Smith struck the first of three quick blows to leave Yorkshire reeling.
He had the cautious Joe Sayers lbw moving across his stumps, found the edge of Andrew Gale's bat to give Ashwell Prince a catch at second slip and nipped one away from Rudolph to have the South African caught behind for 30.
Chapple had to leave the field for treatment with figures of 6-3-6-2 but was able to return after tea which arrived at 79-5, Bairstow having taken 23 deliveries to get off the mark.
Bairstow and Rashid then went for their shots after the interval.
Bairstow twice swept left-arm spinner Simon Kerrigan for four and Rashid glanced Sajid Mahmood to the boundary.
Becoming even bolder, Bairstow then launched Kerrigan high over long on for six but, in trying another big hit off the next ball, he was caught at long off by Smith at the second attempt for 29, the stand having realised 68.
Rashid, partnered by Ajmal Shahzad, continued his bold approach with some enterprising strokeplay, before being trapped by lbw by Smith.
And, despite two powerful fours by Tino Best, he drove Kerrigan hard to deep mid-off to leave his side still in bother at the close.