The sell-out encounter at Home Park had gone virtually the whole match without a goal before Evans broke the deadlock after 81 minutes, with Friio sealing the win just five minutes later.
Bristol City failed to close the gap on The R's after being held at home in a goalless draw by Brighton, while Swindon missed the chance to catch The Robins after crashing to Oldham Athletic.
Goals from Paul Murray and Jermaine Johnson put The Latics in control before Rory Fallon pulled one back, but it proved nothing more than a consolation.
Notts County needed a win at home to Port Vale but were undone twice before the break and were ultimately relegated.
Stephen McPhee and Stephen Brooker put Vale in the driving seat at Meadow Lane. A mountain that proved too steep for County.
Paul Heffernan did get one back for The Magpies but it proved nothing more than a consolation.
Brentford and Wycombe both gained a point apiece at Griffin Park after Matt Harold's goal equalised Nathan Tyson's strike earlier in the half.
Chesterfield claimed all three points from Blackpool after Derek Niven's goal gave them a 1-0 win. Pool's disappointment was completed when Phillip Barnes was sent off late on.
Carl Fletcher gave Bournemouth all three points from their trip to Peterborough after he struck late on to steal a 1-0 win.
Hartlepool United cemented their play-off place with a 2-0 away win over lowly Rushden & Diamonds.
Second half goals from Eifion Williams and Adam Boyd were enough to keep Rushden looking over their shoulder.
Sheffield Wednesday suffered their 17th league defeat of the season after Joey Keith gave Colchester a 1-0 win at Hillsborough.
Early goals from Stockport County were enough to sink Grimsby Town.
Jon Daly and Danny Jackman put The Hatters two-up inside ten minutes, and while Graham Hockless did pull one back, they failed to find an equaliser.
Second half goals from Iain Hume and Ryan Taylor lifted Tranmere Rovers to a 2-0 victory over Barnsley at Prenton Park.
A brace from Hector Sam was enough for Wrexham to beat Luton 2-1. Steve Howard netted for Luton - however their play-off hopes are now over.
Click below for match summaries:
Brentford 1-1 Wycombe
Bristol City 0-0 Brighton
Chesterfield 1-0 Blackpool
Notts County 1-2 Port Vale
Peterborough 0-1 Bournemouth Rangers
Plymouth 2-0 QPR
Rushden & Diamonds 0-2 Hartlepool
Sheff Wed 0-1 Colchester
Stockport 2-1 Grimsby
Swindon 1-2 Oldham
Tranmere 2-0 Barnsley
Wrexham 2-1 Luton
Click here for the latest Second Division table.
