Caversham had the lion's share of possession and territory during the game but a determined and well-organised Roslyn defence, led by central defender James Watson, kept the game locked up until late in the match.
Some skilful play by Caversham striker Ant Hancock clinched the win in the 82nd minute.
Hancock received the ball outside the penalty area, deceived his marker with an excellent turn and attacked the goal, finishing with accuracy and composure to leave Roslyn keeper Peter Evans no chance.
Caversham coach Richard Murray was pleased with banking three valuable points.
"The equivalent game last season, we would have drawn," Murray said.
"We've matured as a team.
"The players know good chances will become evident late in the game."
Second-placed Dunedin Technical took advantage of a fast start, when it scored twice in the first 10 minutes, to stroll to an 8-1 win over a Queenstown Rovers team which was better than the scoreline suggested.
Relatively average form from prolific Technical striker Aaron Burgess in recent weeks was easily forgotten after the deadly finisher knocked in four, including two penalties.
Also showing signs of top form was Alistair Rickerby, with a brace, while Tristan Prattley and Victor De Costa netted one apiece.
Queenstown's scorer was Ian Lowe.
In the early match at the Caledonian, the Plainsmen and their supporters from Mosgiel were treated to a six-goal thriller when they shared the spoils with Northern.
Mosgiel took a handy 2-0 lead midway through the first half when Morgan Day scored twice, including a highlight reel volley.
Northern's Tim Smith netted before the break and Northern was looking odds-on to do the double over Mosgiel when Will Dickinson scored twice to give his club the lead.
However, Ryan McGarry spared Mosgiel's blushes when he slotted the equaliser after his initial shot rebounded directly back to him from the upright.
Green Island, arguably this season's most improved team, dropped three points at home in a 3 -1 loss to University, a difficult opponent for any team when at full strength.
Story by Wilson James.
