The Pilgrims led courtesy of goals from Scott Garner and Kaine Felix but Chorley hit back through Chris Doyle and forced extra-time when Adam Roscoe scored an unbelivable overhead kick to level the tie.

Max Stryjek saved two penalties in the shootout, but Garner, Carl Piergianni and Rene Steer were all denied by Sam Ashton in a dramatic and gut-wrenching conclusion to the Pilgrims' campaign.

Kyle Dixon had been preferred to Grant Roberts from the start in United's only change to Wednesday's first leg stalemate at Victory Park.

United struggled to get going early on against a Chorley side with the wind in their favour although the Pilgrims did create the game's first clear-cut opening with Dayle Southwell's 22-yarder flying wide.

Mark Jones was then unable to get enough purchase on a header following Southwell's hooked cross and Doyle falling over at a crucial time.

Stryjek had to be alert to beat aside Roscoe's 20-yard bullet, but United soon edged in front. Zak Mills' long throw was not cleared and GARNER shovelled home the loose ball to spark delirium among the 2,800-plus home fans.

Four minutes after the break, United doubled their lead when FELIX dribbled through the visiting rearguard to slot the ball past Ashton and seemingly set the Pilgrims on course for a routine win.

Chorley reduced the arrears seven minutes later when Dale Whitham swung over a deep free-kick and DOYLE pounced to score from a tight angle.

The game became stretched in the closing stages and Southwell's brilliant drive flashed to safety off the post, while Nicky Walker's rebound was gathered by Ashton.

With four minutes added time signalled, proceedings were into a fifth additional minute due to an injury to Felix when ROSCOE smashed home an incredible overhead kick to force extra-time.

Chances fell to Walker and substitute Jake Hall at the beginning of extra-time, while Roscoe received his marching orders on 108 minutes for a second bookable offence.

Southwell planted a header wide from Steer's cross in the closing act before penalties arrived.

James Dean, Southwell, Jack Dorney and Mills made it 2-2 after four penalties, while Whitham and Garner were denied by respective keepers Stryjek and Ashton.

Paul Jarvis and Jones then converted, but Matt Flynn was denied by Stryjek and Piergianni, with the chance to win it, saw Ashton divert his high effort onto the underside of the crossbar.

Substitutes Aaron Burns and Jamie McGhee kept the contest alive but once Mark Ross had stroked home his spot-kick, it was left to Ashton to tip Steer's spot-kick onto the bar and spark wild scenes in the away end and leave United contemplating a heart-breaking end to the season.

Boston (4-4-2): Max Stryjek; Liam Marrs, Zak Mills, Carl Piergianni, Rene Steer; Kaine Felix (Jake Hall 90), Scott Garner, Kyle Dixon (Grant Roberts 46), Nicky Walker (Jamie McGhee 110); Dayle Southwell, Mark Jones. Subs (not used): Marc Newsham, Sam Vince (gk).

Chorley (4-2-3-1): Sam Ashton; Mark Ross, Andy Teague (Matt Flynn 57), Chris Doyle, Paul Jarvis; Adam Roscoe, Dale Whitham; Josh Hine (Aaron Burns 63), Harry Winter (Chris Almond 55), Jack Dorney; James Dean. Subs (not used): Jake Cottrell, Adam Mather.

Referee: Tom Nield.

Attendance: 3,174 (319 visitors).

PIC: Tim Hoff.