The young goalkeeper, who joined Derek Adams’ men on a season-long loan deal earlier this summer, saw Adam Phillips give his side an early lead at Blundell Park.
The 21-year-old was beaten by Matt Green’s effort before the break as the Mariners levelled, but with the contest still level after 90 minutes, Turner took centre stage in the ensuing shoot-out.
James Tilley and James McKeown were both denied from the spot by the former Bolton stopper, with John O’Sullivan stepping up to convert the decisive penalty and earn the League Two outfit a 4-3 victory on penalties.
Morecambe will now host Oldham in the next round and, should they progress, Turner and his side could be drawn against some familiar faces, with the winners of that tie set to welcome the winners of Newcastle’s second round clash against Blackburn Rovers in the third round.
Meanwhile, defender Kell Watts enjoyed a fine start to his season on loan at Plymouth Argyle, playing the full game as Ryan Lowe’s men beat Championship side 3-2.
Watts, who made his Premier League debut for the Magpies against Liverpool at the end of last season, lined up in the heart of defence for League One’s Argyle as they made sure of their place in the second round thanks to Frank Nouble’s 78th-minute winner.
Plymouth’s reward for that upset is a trip to League Two side Leyton Orient next week - with the winners of that clash due to host Jose Mourinho’s Tottenham Hotspur in the third round.
Another pair of United loanees, Tom Allan and Mo Sangare, both made their debuts for Accrington Stanley as they were beaten by penalties by Burton Albion at the weekend.
Forward Allan started for John Coleman’s men before being replaced just before the final whistle, while midfielder Sangare stepped off the bench on 65 minutes before stepping up to slot home a spot-kick in the shoot-out.
It wasn’t to be for Accy, though, as the Brewers prevailed, but both players could now feature in another cup competition as Stanley welcome Leeds United under-21s in the EFL Trophy on Tuesday.
It wasn’t a memorable weekend for Freddie Woodman, however, as his Swansea City side were beaten 2-0 at Newport County.
Tristan Abrahams’ brace was enough to send the Exiles through at the expense of the Swans, who Woodman joined for a second successive season on loan earlier this summer.
