Yuvraj`s figures of five for 31 are best by a left-arm spinner in the history of World Cup as Ireland were all out in 47.5 overs.
Put into bat after Mahendra Singh Dhoni won the toss, Ireland lost two early wickets to Zaheer Khan before rival captain William Porterfield rode on an early reprieve to rescue the team from a precarious situation.
The Ireland skipper, who was dropped for nought by Yusuf Pathan standing in the slips of the second ball of the match bowled by Zaheer, ensured that he capitalised on his `life`.
Porterfield (75 off 104 balls) along with Niall O`Brien (46 off 78) put on 113 runs off 148 balls for the third wicket to put his team back on track, but the skipper`s dismissal at a crucial juncture allowed India to fight back into the match at the Chinnaswamy Stadium here.
During his 146-minute stay in the middle, Portefield hit six boundaries and a six, while Niall O`Brien?s knock included three hits to the fence. Alex Cusack made 24 of 30 balls, but overall, the Irish line-up found Yuvraj too difficult to handle on a track where batting never looked the most hardest thing in the world.
After the two early blows, it was more about a battle for survival for Ireland. But Portefield and Niall O`Brien both showed gumption during an association, which not just steadied what seemed like a sinking ship a little while ago, but also yielded runs on the board.
They did a sensible thing by not taking on Zaheer, who was moving the ball both ways, but more than made it up with their cautious approach against Zaheer by milking the spinners.
Runs came at a healthy pace as long as the two were in the crease. Apart from an attack that lacked bite, the Irish duo was also helped by some sloppy ground fielding by the Indians, though Virat Kohli made up for his few few lapses by running out the senior among the O`Brien brothers.
But before that, for 93 minutes and 148 deliveries, Porterfield and O`Brien made the Indians sweat with some calculative batting.
The ploy was to attack Piyush Chawla, the weakest link in the Indian attack, and the moment the leggie was introduced just before the first drinks break, Porterfield signalled his intention with a towering six over deep mid-wicket.
Using his feet regularly, Porterfield not only negated whatever turn was there on offer, but also forced Chawla to err in line. The leg-spinner was guilty of bowling too many extras in his first spell, including three wides and a no ball in a single over that left the Indians frustrated for a while.
Soon Porterfield reached his half-century, a well-deserved one, with a drive through extra cover after Chawla dropped one too full and in the zone.
But just when things were looking bright for Ireland, came a steback. Kohli helped Dhoni run O`Brien out with a direct throw from point and it triggered a mini-collapse that saw Ireland lose four wickets for 40 runs, including the important one of Portefield.
Andrew White, inducted in place of Gary Wilson and coming in after the fall of Niall O`Brien, edged Yuvraj to Dhoni for five.
Last match`s hero, Kevin O`Brien, was greeted with much anticipation from a packed Chinnaswamy crowd, but his nine-minute stay ended when Yuvraj had him caught off his own bowling.
The associate nation was dealt its biggest blow when Yuvraj, who was turning things around for the hosts, dimissed Porterfield just after the drinks break. The Irish captain rocked back after seeing a short delivery from Yuvraj but could not clear Harbhajan at cover.
As is often the case with a set batsman, the break may well have disturbed Porterfield`s concentration.
India heaved a sigh of relief, thanks largely to Yuvraj.
His performance with the ball might force the team management to think whether they need an off-colour Chawla in the XI for the matches ahead.
Earlier, barring Zaheer`s opening burst during which he picked up the wickets of Paul Stirling and Ed Joyce, Dhoni kept rotating the other bowlers in the early part of the Ireland innings, with Munaf Patel being replaced twice withing the first 15 overs.
Zaheer gave India an early breakthrough when he went through Paul Stirling`s half-hearted drive with a delivery that swung in off the track.
The left-arm seamer struck again when Ed Joyce edged one to Dhoni after failing to read a ball that zipped inward on landing. What left the batsman foxed was that Zaheer, before that wicket-taking inswinger, were bowling away-going deliveries at will.