Rob Duffy was on target from the spot for the Imps in the first half but this was cancelled out shortly before the hour when Trinity substitute Darryn Stamp headed past Paul Farman.
City, looking resplendent in their new red and white striped home kit, kicked off attacking the Bridge McFarland Stand and, with the sun shining brightly, it was an understandably quiet opening with neither goalkeeper tested in the opening quarter hour.
In fact 19 minutes had elapsed before the first half-chance came along, Jamie Taylor exchanging passes with Rob Duffy before drilling past Jason White's right hand post from the edge of the area.
Gainsborough's first sight of goal came four minutes later with ex-Imp Paul Connor being denied by a fine save by Paul Farman who duly commanded his area well to claim the resultant corner, the first of the afternoon.
The Imps responded to this scare by forcing a corner of their own following good work by Adam Smith down the left; Smith took the kick himself with former Trinity man Andrew Boyce prodding wide when the ball came at him somewhat sharply on the six yard line.
Both sides won further corners as the tempo started to increase but it was a move from open play that led to the opening goal in the 39th minute with a great knock down from Duffy setting Alan Power
free in the box. The midfielder was about to pull the trigger only to be dragged to the deck with referee Brooks having the easy option of awarding a penalty. Duffy took the responsibility from 12 yards and neatly sent White the wrong way to give the Imps the lead.
The goal seemed to bring the Imps to life with Taylor having two efforts sniffed out by the Trinity defence before the lively City striker was robbed again by White after he robbed Lee Ridley of the ball close to the byline.
The first chance of the second half saw Taylor denied by Trinity substitute Jan Butdz and the latter denied the former again 10 minutes after the restart with the City striker still having no luck in front of goal as the game wore on.
In the 57th minute there was a worrying sight as Alan Power
was forced off the field after taking a knock; Paul Robson was his replacement as Power was helped towards the dressing rooms with Dan Gray pushing forward into a midfield role as a result of this enforced switch.
Although City looked to be in control, it was Trinity who bagged the second goal of the game seven minutes later when Darryn Stamp, who replaced Ryan Williams at the same time as the above change, stooped to meet a low cross from the right before planting a firm header past Farman from eight yards out.
It was all change midway through the half with Jake Sheridan, Bradley Barraclough and Richard Pacquette, back at the Bank on trial, coming on for Peter Bore, Jamie Taylor and Rob Duffy whilst for Gainsborough ex-Imp Danny Hone was given a run out in familiar surroundings. Former Cheltenham Town centre-back Gavin Caines, also on trial, Nicky Nicolau and Tom Miller then replaced Andrew Boyce, Adam Smith and Graham Hutchison.
After this stop-start period, Stamp had the next half chance with the striker curling a long-range effort over the bar whilst at the other end good work from Barraclough saw him cut in from the left before firing wide of the mark.
Barraclough was involved in the next move of note, with the substitute again cutting in before crossing for Gray who delayed his first effort before seeing his eventual shot palmed away by Butdz.
With three minutes remaining a foul on Nicolau gave the Imps a chance from a set-piece in a dangerous position but John Nutter was left holding his head as his left-footed curler flew inches past the right hand post.
City continued on the offensive as the game wore on with Nicolau firing a powerful drive past the other upright from 25 yards out and this proved to be the last action with the friendly match ending all-square.
Paul Farman, Dan Gray, Andrew Boyce (Gavin Caines 72), Graham Hutchison (Tom Miller 72), John Nutter, Gary Mills, Alan Power
(Paul Robson 57), Adam Smith (Nicky Nicolau 72), Peter Bore (Jake Sheridan 68), Rob Duffy (Richard Pacquette 68), Jamie Taylor (Bradley Barraclough 68).
subs not used: Geoffrey Gouveia, Jake Turner.
goal: Duffy (39 pen)
Trinity: Jason White (Jan Butdz h/t), Dominic Roma (Danny Hone 70), Lee Ridley (Josh Wilde 62), Luke Waterfall, Greg Young, Michael Leary, Jonathan D'Laryea, Ryan Williams (Darryn Stamp 57), Shane Clarke, Paul Connor (Craig Nelthorpe 78), Jamie Yates (Terry Hawkridge h/t).
subs not used: Jonathan Williams, Sam Mulready.
goal: Stamp (57)
Referee: John Brooks
Assistants: Martin Chester & Paul Wood
Attendance: 879 (114 away supporters)