The sides were contesting the final Group A fixture before both move on the next stage and the Irish were outclassed from the off as Zaheer Khan ripped through their top order with four for 19.
They eventually struggled to a respectable 112 for eight in their 18 overs but India cruised home with 2.3 overs to spare as Rohit Sharma clubbed 52.
There is no let-up for Porterfield’s men though, with injury-plagued New Zealand next up.
And the opening batsman insists he is not content with valiant defeat against a Black Caps side who are struggling to muster 11 fully fit players.
“We’re not too concerned with the New Zealand situation. Obviously it would be a boost to us if they struggle but as long as we concentrate on ourselves and our own 15 are fit and available, then that is best for us,” he said.
“We’ve spoken about the fact that it doesn’t matter what team we play against in this tournament or who is at the other end.
“When you cross the white line it’s 11 versus 11 and man against man.
“We’re just going out to be competitive and do what we do and I think we did that against India.”
The Gloucestershire batsman added: “With a bit of luck going our way and if we can play to our potential we are capable of causing upsets.
“We will go out with a plan to win the game.
“We want to get our Super Eights off to a winning start and why not?
“We knew today was going to be a big step up from Bangladesh but this is why we’re here. We want to play the best teams in the world and we aspire to get nearer and nearer to those teams.”
Porterfield said former captain Trent Johnston would return to the side today, having been rested for this match, with Andre Botha looking most vulnerable.
Andrew White, though, may have done enough to keep his place after top-scoring with a counter-attacking 29.
India begin their Super Eights campaign tomorrow against the West Indies at Lord’s and the in-form Zaheer, only recently back in the side following a shoulder problem, has already targeted their main man.
“Chris Gayle is definitely a match-winner. It will be a good to take his wicket early,” he said.
“If we can get him out early it will be a big help.”
The evident gulf in class last night was nonetheless a stark warning of what Ireland will be up against in the remainder of the tournament.
Opener Jeremy Bray struggled before he was comprehensively bowled for a seven-ball duck by Zaheer. His opening partner Porterfield soon slashed a catch to slip off Zaheer – and after Andre Botha had also guided another one to the same position from the same bowler, at 17 for three it seemed a short match was in prospect.
But a late surge saw ninth-wicket pair Alex Cusack and Kyle McCallan bag 20 runs from the last 10 balls but it was a target which was always unlikely to tax India too much.
Indian openers Gautam Gambhir and Rohit Sharma played with great assurance, and it looked as if they would take India to a ten wicket win as they put on 77 in 10.5 overs. However the introduction of spin in the form of Regan West gave the Irish the breakthrough, as Gambhir cut straight to Rankin at point.
MS Dhoni was troubled by a few real lifting deliveries from Boyd Rankin early on, who impressed up until his final delivery, which Rohit Sharma deposited out of the ground.
Kyle McCallan picked up the wicket of Dhoni, brilliantly caught by Jeremy Bray at deep square leg. Sharma brought up his 50 with a drive over cover, reaching the milestone from 44 balls, which included 4 fours and a six. The next ball was pushed for a single and the victory achieved with ease.