After leading by 25 points at the start of final term, Box Hill were unable to match the pace of the opposition, scoring only a single goal in the final quarter.
Port Melbourne recruit Dean Galea proved the difference, kicking seven goals straight with three coming importantly in the final term.
Hawthorn defender Ryan Schoenmakers was the best of the Box Hill side with 20 disposals, followed by Liam Shiels (29) and midfielder Ed Curnow (31).
Fielding twelve AFL listed players, Box Hill had the chance to win the game comfortably, but lost a match it should have won easily.
The Hawks struggled to hold off the bigger-bodied forwards of Port Melbourne, with the loss of Cameron Pedersen due to a single week suspension handing the opposition a vital advantage.
After an even opening, Box Hill led by three points at quarter time with efficient kicking in front of goal keeping Port Melbourne in the match.
Port Melbourne placing on the afterburners toppled Box Hill’s lead to take a nine point lead midway during the second term. Goals to Gary Moss, Ryan Schoenmakers and Jayden Hoegel gave Box Hill a slight but handy one point lead at the major break.
Box Hill surged to a 25 point lead after kicking seven goals in the third term, but Port Melbourne never backed down pulling back the margin to take the match in the dying stages by three points.
Ill-disciplined, Port Melbourne constantly were disturbed by the pressure of the Box Hill side, giving away free-kicks and fifty metre penalties with most resulting in Box Hill goals.
Port Melbourne were able to manufacture a better final quarter than Box Hill with the decisive play formed by former Box Hill follower Nathan Batsanis who spotted out Dean Galea leading to the winning goal.
Box Hill looked a lot slower in the final stages, as the speed of the opposition midfield sped up.
Cruel, the loss is somewhat similar to the match against Coburg in Round 3 when the Hawks lost in the 34th minute with a goal in the final stages, after the side had a safe lead.
It also mirrors the loss Box Hill had against Port Melbourne in the VFL First Semi-Final last year, when the Hawks lost in one of the biggest battles by only four points.
A lot can be learnt from the loss, particularly the Hawks final quarter efforts where the team faulted.
Haydn Kiel continued his strong form with 19 disposals with a key role in defence, while Hawk Michael Osborne (23) trying hard all day and kicking 2.1.
Garry Moss (25) and Sam Gibson (19) were also solid contributors in a team that played well all day, falling only at the final hurdle.
Marco Bello also played his 50th match for Box Hill in front of a healthy Box Hill City Oval crowd.
Next week, all VFL teams have a bye with the VFL/WAFL State Match taking precedence on Saturday 22 May.
The VFL/WAFL State Match will be shown on ABC TV from Medibank Stadium, Perth.
Western Australia have not beaten Victoria since a State of Origin win at the WACA Ground in 1991 and are aiming for a win against Victoria for the first time in two decades following a big loss in 2007.
Box Hill is represented by four players in the initial VFL State Squad. Hawthorn’s Luke Breust, and Box Hill’s Ed Curnow, Sam Gibson and Cameron Pedersen are all possible selections for the final team.
After the week off, Box Hill will meet Williamstown on Saturday 29 May at Burbank Oval.
Captain Steve Kenna and midfielder Luke Ablett will be possibilities to return from injury.
Box Hill Hawks: 4.4 / 8.7 / 15.9 / 16.12.108
Port Melbourne: 4.1 / 8.6 / 11.8 / 17.9.111
Goals: S. Gibson 3, B. Fagan 2, G. Moss 2, J. Hoegel 2, M. Osborne 2, L. Shiels, R. Schoenmakers, J. Lisle, T. Duryea, J. Morton
Best: R. Schoenmakers, L. Shiels, E. Curnow, H. Kiel, M. Osborne, S. Gibson