Greg Harding identified a tough and experienced back line as the key to beating South Fremantle last Friday night, which has improved Swan Districts' chances of playing in the second semifinal.
The coach knows a sound defence is critical to finals success and will have another chance to examine his defenders under pressure in the litmus test against premiership favourites Claremont on Saturday.
Swans have given up an average of 92 points a game this season - only the fourth best defensive record in the league - but the team has rarely been better served by its back line than in the fighting 35-point win over the Bulldogs at Fremantle Oval.
Full-back Tallan Ames gathered the ball 10 times in the first term to stymie a series of South Fremantle onslaughts, while the unheralded Justin Simpson and Jarrad Blight were critical in weathering the initial storm.
"The back six were unbeliev-able," Harding said after the 17.18 (120) to 13.7 (85) result.
"When we were under pressure early and we had no momentum (Kyle) Hams, Simpson, Ames and Blight were fantastic.
"They don't normally get much credit, but we were beaten through the midfield and had to battle up forward.
"Simpson took six or seven contested marks while we gave Hams a role where he allowed his man to go up into the play and he became the quarter back.
"He did that the whole game, but early on when we had no momentum, him and Ames were fantastic."
The young Bulldogs started superbly and were still in the match in the third term, when the lead changed six times.
Swans' cream rose to the top in the last quarter with Ash Hansen shrugging off Brendon Gulley, the silky Dayle Garlett proving why he is on the radar of so many AFL recruiters and the experienced midfielders finally emphasising their quality.
Swans can challenge Claremont if they get their best 22 players on the field, but Harding was highly impressed as he watched the Tigers demolish Perth on Saturday.
Half-backs Ryan Davis (ham-string) and Wayde Twomey (knee) could not be considered last Friday and AFL players Murray Newman (knee) and Lachie Neale (quad) will be monitored closely.
Harding was pleased with the debut of 18-year-old Aidan Smith, another talented Aboriginal player from the Midvale area whose superb kicking skills makes him a player to watch.