Tigers, who were without 11 players away on Test duty, made nine changes to the squad that beat the Maori All Blacks just five days earlier.
Director of rugby Richard Cockerill handed first home starts of the campaign to Rob Hawkins, Rob Andrew, Alex Lewington, Andy Forsyth, Michael Noone, Micky Young and Brett Deacon, who captained the side.
And Slater said the contribution throughout the squad underlined the importance of the competition.
“We’re going to take a lot of confidence out of that,” said Slater. “You look at Fraser Balmain and he’s developing well and he got a good test against Alex Corbisero, an international prop.
“Michael Noone got a run out and Brett Deacon was strong for us as captain. It’s massive for squad morale to get a lot of game time and the LV= Cup provides that for some of the boys who probably aren’t there week in, week out.
“I think the character that we showed when Boris got sent off was huge. It felt like we were defending out there for 10 to 15 minutes and we held them out a couple of times. It was a big effort from everyone and we wouldn’t expect anything less.”