The Shrimps dismantled Pompey in an impressive first-half display, as Tom Barkhuizen, Alan Goodall and Andrew Fleming all scored for the away side.
Morecambe led 3-1 before the break, with Gary Roberts clawing a goal back for the hosts minutes before half-time.
Roberts scored again in the second half before Enda Stevens received a second yellow in the 72nd minute, seemingly dooming his team to an unassailable task, but Stockley snatched a draw for his side moments before the final whistle.
Leyton Orient continue to lead the fourth tier table, with a 3-2 win over Newport County, but Plymouth Argyle remain hot on their heels after seeing off Northampton Town 2-0.
Yeovil Town pulled off an impressive comeback from two goals down with a 3-2 win over Luton Town, Ryan Bird's second-half brace helping the hosts to all three points.
Aaron Pierre netted a 95th minute equaliser for Wycombe Wanderers against Dagenham & Redbridge in a 1-1 draw, after their goalscorer Matt McClure was sent off for picking up two yellows.
Teddy Sheringham picked up his first win as Stevenage manager in a 2-0 win over Hartlepool United, Fraser Franks and Brett Williams grabbing the goals to end the visitors’ winning start to the season.
Bristol Rovers continue to climb the table as Lee Brown, Matt Taylor and Jermaine Easter's goals helped the Pirates to an impressive 3-1 win against Barnet.
Roarie Deacon's brace was enough for Crawley Town to see off Cambridge United, the 23-year-old’s first goals for the club adding to Gwion Edwards’s late tap-in for a heavy 3-0 win.
Jabo Ibehre’s goalscoring run continues as his 67th-minute equaliser rescued a point for Carlisle United against AFC Wimbledon, Andy Barcham’s goal nine minutes before the break not proving enouth.
Kemar Roofe's second-half penalty gave Oxford United a share of the spoils in their 1-1 draw against Mansfield Town, with ex-Notts man Craig Westcarr giving the Stags an early lead against the U’s.
Finally, Exeter City and York City played out the only goalless game in this weekend's round of League Two fixtures.
Results in full:
Bristol Rovers 3-1 Barnet
Cambridge Utd 0-3 Crawley
Carlisle 1-1 AFC Wimbledon
Exeter 0-0 York
Mansfield 1-1 Oxford Utd
Newport 2-3 Leyton Orient
Northampton 0-2 Plymouth
Notts County 1-1 Accrington
Portsmouth 3-3 Morecambe
Stevenage 2-0 Hartlepool
Wycombe 1-1 Dagenham & Redbridge
Yeovil 3-2 Luton
The table is as follows:
As previously mentioned, Leyton Orient lead the table with four wins out of four, with Wycombe two points behind them in second. With it being early days, there's a lot of movers all over the place, as Plymouth edge themselves into third place and Bristol Rovers rise to fourth, while Hartlepool, Portsmouth and Cambridge all slip. Notts drop to 16th while, at the foot of the table, Newport slip to 23rd, with Dagenham & Redbridge propping up the table in 24th.
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