THE 39TH Western Derby appears to be one of the most unpredictable to date. The stake are high, with the loser set to stumble to 3-4 and out of the top eight after both sides started the season with a 3-2 record. Both teams are also coming off losses after leading in the last quarter. North Melbourne humbled Fremantle at home while West Coast blew a 24-point lead with 10 minutes to play against Carlton. The ruck duel is arguably the most fascinating aspect to this Derby. Both Aaron Sandilands and Nic Naitanui have had their value questioned in recent weeks, Dean Cox continues to be a constant threat while Zac Clarke is still developing his game. The true value of winning the ruck battle might be revealed this week.

WHERE AND WHEN: Patersons Stadium, Sunday May 4, 2.40pm

TV AND RADIO: Click here for the broadcast guide

R16, 2013, Fremantle 19.7 (121) d West Coast 14.9 (93) at Patersons Stadium
R1, 2013, Fremantle 16.12 (108) d West Coast 11.14 (80) at Patersons Stadium
R19, 2012, Fremantle 17.11 (113) d West Coast 6.12 (48) at Patersons Stadium
R9, 2012, West Coast 11.18 (84) d Fremantle 5.6 (36) at Patersons Stadium
R18, 2011, West Coast 8.17 (65) d Fremantle 9.10 (64) at Patersons Stadium

1. This will be the 39th Western Derby and West Coast holds the advantage, winning 21 games to 17. However, the Dockers have won 14 of the past 22, including the past three.

2. The ruck battle will be intriguing. Fremantle is the No.1 team for hit-outs in 2014, averaging 56.3 per game. West Coast is ranked third with 47.3 per game.

3. Despite both teams possessing dominant ruckmen it has not translated into centre clearance dominance. Fremantle is ranked 14th in the AFL and West Coast is equal 15th.

4. Former West Coast full-forward Scott Cummings holds the record for the most goals kicked in a Derby. He kicked 10 in round six, 2000.

5. Fremantle is ranked second in the AFL this year for contested possessions, averaging 148.7 per game. West Coast is ninth with 140.5 per game.

6. The discrepancies in the rankings of both sides' ruckmen is startling. According to the Official AFL Player Ratings, Nic Naitanui is the highest-rated ruckman in the AFL (21st overall) while Dean Cox is sixth (112th overall). Freo star Aaron Sandilands is the 15th ranked ruckman (No.239 overall) and Zac Clarke is 18th (No.293 overall).

Prediction: Fremantle by six points