The Demons held off the Tigers' last quarter push, helped somewhat by Richmond's inaccuracy in front of goal, to virtually consign the Tigers to the finals scrap heap.
A week after letting slip a four-point three-quarter time lead to the Western Bulldogs, Melbourne held its nerve to close out its third win of the season.
"It was a great win," Roos said after the match.
"Three-quarter time, similar circumstance playing against a team that obviously had a lot to play for… for us to get over the line was a real positive for the players and the club."
The Demons' win was built on the type of effort and attitude players display when they are enjoying their football.
But most importantly, the victory was fostered through hard work, highlighted by the 16 tackles laid between key forwards Chris Dawes and Cam Pedersen.
Roos said the win was a significant step for his young players.
"We are coming from a long way back, so I was really pleased that we kept persevering, and to win today is really important."
Dom Tyson (23 disposals) continues to grow in stature by the week and Nathan Jones leads from the front like no-one else at the club (33 possessions and nine clearances), while Jack Watts (career-high 11 marks) is thriving now he is settled in the forward line.
But it was the performance of Pedersen and Dawes, and to an extent Max Gawn, which earned the most plaudits from the coach.
In what was almost certainly his best game for the Demons, Pedersen kicked two goals, raked in eight marks and collected the ball 16 times in a superb display.
Roos said having multiple options up forward was a key yardstick in the Demons' improvement.
"Not having Dawes (at the start of the season) really hurt us. You probably don’t realise until we get them back into the team," Roos said.
"Just his competitiveness and ability to fight and work, allows Pedo (Pedersen) to get the next best sort of defender. I thought Pedersen was terrific."
However, memorable wins like the one over Richmond do not influence Roos' decision making around the expiration of his two-year (with an option of a third year) coaching contract at the end of 2015.
The Demons are waiting on Roos to make a firm commitment, but are getting set to interview a field of likely successors beginning at the end of this season.
"It probably makes me feel better in the short term because I'm aware of the pain this club has had for so long, even though I wasn’t here, you tend to feel it," Roos said.
"I don't really think too much about the longer term stuff, it's probably the short term stuff for the people who have endured so many hard times; it's good to see the Melbourne fans celebrating after the game."
Melbourne now has the bye week, which Roos plans to use to review the first half of the year, before a meeting with top-of-the-table Port Adelaide in Alice Springs on May 31.
Twitter: @AFL_BenGuthrie