A century to skipper Alistair Taylor appears to have Launceston in the box seat after day one of the Cricket North grand final.
Riverside made late inroads to eventually have the Lions 7-279, but had few answers in the middle session as Taylor (109) and James Curran (55) put on 159 for the fourth wicket.
Taylor's three-hour knock featured an array of glorious cover drives, pull shots and a windmill celebration upon reaching three figures for the fourth time this season.
"I was pretty driven to try and do well for the boys," Taylor said.
"I tried to take it on myself when we lost three wickets to counter-attack and it paid off.
"I couldn't have done it without James Curran at the other end, he played a massive role in keeping me calm as well which is really impressive for a young player."
Riverside looked in trouble with the Lions at 3-219 before Cooper Anthes sparked hope shortly before tea.
Brought on as the Blues' eighth bowler, the teen sensation had Taylor caught behind before drawing Curran into a false shot an over later.
Sam Lockett got one to rear up on Ben Humphrey not long after tea before the Lions shut up shop for the day's remainder.
Will Bennett (24) was the only other wicket to fall - edging Lyndon Stubbs (3-44) to gully - as the experience of Rowan Smith (12 off 93) and Tom Gray (15 off 49) guided the Lions to stumps.
MORE SPORT: Launceston TSL season preview
Earlier, Lockett and Stubbs took the opening wickets after sending the Lions in, with Cam Lynch trapped in front and Dilan Sandagirigoda (30) falling to a diving catch from Pete New, who was keeping up to the stumps.
Both skippers agreed there was still plenty of runs left in the wicket, with Taylor hoping to post well over 300 and Tom Garwood setting his sights on polishing off the tail first thing Saturday morning.
Garwood said tight bowling and a change in the opposition's gameplan had led to runs drying up in the final session, and backed his side's batting line-up to make their own statement.
"Obviously Cooper took two quick wickets which was really good, but Rama [Ramesh Sundra] bowled really well," he said.
Play continues from 11am on Saturday and Sunday.