Lancashire 137 and 226 for 5 (Wells 102) need another 247 runs to beat Glamorgan 261 and 348 for 7 dec (Northeast 132, Carlson 108)
Two sessions of dominance by promotion-chasing Glamorgan will see them go into the final day of this Rothesay County Championship Division Two clash with Lancashire as favourites despite the hosts giving themselves a sniff of an unlikely victory with a thrilling counterattack.
Both skipper Sam Northeast and Kiran Carlson scored centuries as the visitors took their overnight score from 95 for 2 to 348 for 7 by the time they declared just before tea with a lead of 472 and a minimum of 147 overs in which to dismiss Lancashire.
In contrast to the first two days, where spin dominated, the Red Rose bowlers toiled, with Northeast and Carlson able to build a huge third-wicket partnership of 215.
Although Chris Green finished with three wickets and match figures of nine for 175 the writing looked to be on the wall by the time Northeast stuck Lancashire in, only for Luke Wells to score a century of his own and leave the home side requiring 247 runs with five wickets in hand.
Glamorgan set about things at a measured pace with Carlson reaching his second half-century of the game in the third over of the day.
When captain James Anderson turned to Green, Northeast and Carlson ensured the Australian did not repeat his first-innings heroics by attacking both him and the left arm spin of Tom Hartley.
Carlson progressed to his century off 120 balls and it took the introduction of Wells' leg-spin to break the third wicket partnership when he trapped the Welshman in front for 106.
The incoming Colin Ingram joined Northeast and immediately attacked, hitting 34 off 29 balls before he was stumped by Salt to give Wells his second wicket.
Meanwhile, the experienced skipper was playing the sort of innings he has been for years with the 35-year-old bringing up his 35th first-class century off 183 balls before Ingram's dismissal.
Northeast eventually departed for 132 caught on the leg side boundary by sub Jack Blatherwick off Green prompting Glamorgan to have a dash in the pursuit of quick runs resulting in the wickets of Ben Kellaway (19) lbw to Green and Crane by the same bowler for one.
Tea was followed by Lancashire beginning their reply with the attack-minded Salt joining Wells in the middle and soon returning to the dressing room after he edged James Harris to Ingram at first slip for one.
Nevertheless Salt's introduction showed some intent and that's exactly what Lancashire displayed from then on with Wells leading the way.
The former Sussex man and Keaton Jennings put on 72 for the second wicket before Lancashire's ex-captain was caught smartly by Asa Tribe at short leg off a big turner from Crane for 33.
Josh Bohannon then joined Wells and the third wicket pair began to give the hosts a glimmer of hope as they targeted Crane and injected some energy into the innings.
82 runs were hit off 10.2 overs with extravagant shots combining with frantic running to suddenly put Glamorgan on the back foot for virtually the first time in the match.
Order was restored when Bohannon edged Asitha Fernando behind for 29 but with Wells reaching his century with a booming six off Kellaway before he was brilliantly caught and bowled by James Harris for 102, leaving the dangerous Marcus Harris and the in-form Matty Hurst at the crease, hope still sprung eternal for the watching home crowd.
Some of that hope dissipated when Hurst was bowled by a sharply turning delivery from Kellaway for 11 but with the likes of George Balderson, Green and Hartley still to come after Tom Bailey's elevation to nightwatchman, an unlikely and record breaking run chase could still be on the cards.
