But, after Ludovico Nitoglia had reduced the arrears, Murrayfield erupted as Paterson went over the try-line for his farewell try before retiring.
Edoardo Gori dulled the celebrations when he went over for Treviso moments later but Tim Visser's 13th RaboDirect PRO12 try and another for the departing Kyle Traynor helped the Gunners ease to victory.
Laidlaw kicked Edinburgh into the lead with a penalty after just four minutes, having refused an attempt at goal moments earlier.
Kris Burton missed the chance to draw Treviso level with a penalty of his own after eight minutes and he would be made to pay as Edinburgh spent the rest of the half establishing a comfortable lead.
And after some patient play, Edinburgh had the first try of the game just before quarter of an hour as Laidlaw's delayed pass allowed back-row Denton to touch down to the left of the posts.
After Laidlaw had added the extras the fly-half kicked another three-pointer ten minutes later as the Gunners stretched their lead to 13-0.
Visser thought he had extended his lead atop the RaboDirect PRO12 try scoring charts when he went over midway through the half but the referee judged Nick De Luca's assist to be a forward pass.
But after Treviso went down to 14 men, with Alessandro Zanni shown a yellow card, Edinburgh did grab the second try of the game as captain Laidlaw dummied before running through to cross the whitewash, picking himself up to kick the conversion.
However, just two minutes later a mix-up in the Edinburgh midfield allowed Treviso to get on the scoresheet, Benvenuti going over in the corner.
But after Burton added the extras Laidlaw booted another penalty for the hosts as they headed into the break 23-7 ahead.
After a scrappy start to the second-half Treviso's ill-discipline let them down again as Brendan Williams, not long on as a replacement, was sent to the sin-bin for a deliberate knock on.
But despite being a man down Treviso helped themselves to their second try of the game on 53 minutes as Nitoglia touched down, Burton adding the conversion.
The Murrayfield crowd were on their feet as Alan MacDonald replaced Denton on 52 minutes for his final Edinburgh appearance, but there was a far louder cheer just moments later as Paterson scored his fairytale try.
The full-back ran on to a chip through to score, leaving the home fans delirious, Laidlaw doing his best to keep his nerve as he kicked the conversion.
The home fans were brought back down to Earth five minutes later as Gori caught Edinburgh napping to reduce the arrears.
But there was still plenty to celebrate as Visser crossed the whitewash with ten minutes remaining and Laidlaw converted, before Paterson left the pitch with two minutes remaining to a standing ovation.
And the crowd had barely sat down again before they were waving goodbye to another player, Traynor going over for Edinburgh's fifth of the evening, Laidlaw adding the extras.
|Edinburgh Rugby Score Card|
|Benetton Treviso Score Card|