"We'll take that and it was good to get the bonus point. It was a good performance and we took our chances," he said.
"The forwards played well and it's a good start. The guys that we have brought in are doing well and the younger guys are stepping up."
Tries in the first half from Nicholas Andrews and Richard Fegan set Instonians on their way at Shaw's Bridge, with Alan Whitten, Joshua Devitt and Chris Morgan touching down in the second half as the Belfast side secured the bonus point.
Out-half Rory McCann top scored for 'Inst with 15 points - three conversions and three penalty goals.
The South v North Dublin derby at Merrion Road went the way of Wanderers - 19-6. Full-back Michael Boland kicked 14 points and hooker Alan McMahon scored a try as a game Suttonians outfit were swept aside.
Beginning their 14th consecutive season in the AIB League, Suttonians will be hoping to bounce back at home to County Carlow next week.
Carlow themselves suffered an opening defeat, going down 26-3 to newcomers Navan. The Meath men secured a satisfying bonus point for their trip back from Oak Park, thanks to tries from busy scrum half Kieran Mattson, Shane Dawson, David Geraghty and Tongan Mata Fifita.
Carlow, with a number of new players on board, struggled to find their rhythm and disappointed at set piece time, particularly in the lineout.
Helped by their solid set piece, Navan led by 12-3 at the break. Player-coach Brad Harris was back to his influential best in the second row, alongside the equally effective Paul Feeney.
Meanwhile, Queen's University were Ulster derby winners on the first day as they saw off Banbridge 24-6 at Dub Lane.
In a scrappy first half Chris Quinn and Richard Thompson exchanged penalties to leave the sides level at half-time.
Second half tries from Ulster Academy prop Paul Karayiannis, Michael Ferguson and James McKinney were enough to give the students a deserved victory.
Rainey and Ards both suffered disappointing home defeats.
The Old Boys went down 12-3 at Hatrick Park against Sunday's Well but more crucially suffered to key injuries.
Kiwi Tom Dudonski and lock Conor Lavery were forced off early and to compound Rainey's misery they were denied a bonus point when the Cork side scored a last minute penalty.
Ards did manage to take a bonus point in their 26-20 by Barnhall at Hamilton Park.
It was a disappointing result Ards after they had led 12-6 at the interval with Michael Lawton slotting over four penalties.
Lawton added another kick after the break but the visitors' pack started to edge the forward battle and created tries for Darryl Furlong and Paul Burke.
Ards salvaged something from the game when the pack created a try for Ajay Derwin.
AIB LEAGUE DIVISION 3 RESULTS: Saturday, October 3
Ards 20 Barnhall 26, Hamilton Park
County Carlow 3 Navan 26, Oak Park
Instonians 40 Portadown 5, Shaw's Bridge
Naas 10 Midleton 16, Forenaughts
Nenagh Ormond 44 Connemara 13, New Ormond Park
Queen's University 24 Banbridge 6, Dub Lane
Rainey Old Boys 3 Sunday's Well 12, Hatrick Park
Wanderers 19 Suttonians 6, Merrion Road