Mowbray showed signs of things to come as its young guns fired to keep Launceston in the hunt for finals.
A 5.30pm deadline and seven runs was all that came between the Eagles' first Cricket North scalp this season as the home side's chase of Riverside's 244 ended at 7-237 after 55 overs.
Resuming at 5-127, Riverside lost its main man Peter New for 80 but steadied through key knocks from Matthew Kerrison (47) and Ramesh Sundra (37 not out).
ELSEWHERE IN SPORT
Sundra put on 41 for the last wicket with Jesse Homan (5) to see Riverside within two overs of an enforced declaration before Spencer Hayes (2-15) ended the innings in the 73rd over.
Hayes then proved the hero with the bat, belting two sixes and 10 fours in a career-high 85 to compliment a useful 39 from Luke Scott.
"Spencer batted really well," Mowbray coach James Storay said.
"I know what his talents are and that he is definitely capable of performing really well at that level.
"It was good to see reward for effort but I'm a little bit shattered for him that he left a ton out there, he was hitting the ball really cleanly and played a really mature knock for that type of run chase."
Fellow young gun Lochie Geard (60*) started slowly but led the chase following Hayes' dismissal and notched a maiden A-grade half-century.
The Eagles needed 15 runs off the final over to secure an unlikely victory but were kept to just eight as Riverside's most dangerous bowler Patty Mackrell (3-45) removed Luke Burston via the safe hands of Josh Partridge.
"We were very close to a team that's probably going to play finals, so it shows that we are good enough to compete with these teams," Storay said.
"I'm really proud of the way they went - it was a 'let's win this game of cricket' not 'let's go into our shells and play for a draw'. Even though that was the result we always had winning at the front of our mind and they applied themselves really well."
SOUTH LAUNCESTON kept things tight at the top of the table by holding reigning champions Westbury to a draw at the NTCA No.2.
Starting the day at 2-74, the Knights batted their remaining 50 overs to set a mountainous 5-300.
After losing his partner Sean Harris to Matthew Battle (2-62) early in the day, Knights captain Tom Waller found a steady partner in Nathan Philip.
Left-hander Philip went on to post his second ton of the year - a 128-ball 107 not out - and batted nearly 40 overs with his captain in a 163-run stand before Waller was stumped for a career-high 79 off wily spinner Kieren Hume (3-70).
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"I was close there, we were going for some quick runs there at the end but it was nice to bat with Flip, he's a class player," Waller said.
"It was just really nice to bat on a nice wicket with a nice outfield - it makes a difference that's for sure, especially for nickers and nudgers like me.
"There were a lot of runs scored so it was a bit hard to get a result, but we'll take 300 runs off 70 overs, that's for sure."
Westbury made 5-155 off its 48 overs with Matthew Battle (77) and Dan Murfet (26 off 70) putting on 54 for the second wicket.
Anders Bulow, Jackson Young and Graham Donaldson took a wicket each for the Knights.