This article is part of a series in the lead up to India's first match at the World Cup. India at the World Cup will explore India's highs and lows over the years in cricket's premier tournament.

About 6 minutes into Led Zepp's Stairway to Heaven, you can hear Jimmy's Page's minute-long guitar solo. And at this point, you are so taken by the song that it just seamlessly flows through your veins.

Source: Louder

That is exactly how it felt when an in-form Yuvraj Singh batted the way only he could.

Source: Batting with Bimal

Everything about it was perfect, flawless and pure in every sense of the word.

Source: Cricket world cup

But that was not the case during the 2011 World Cup. Or even a year leading up to it.

Source: Espncricinfo

The last big tournament before the World Cup was the Asia Cup in 2010 but Yuvraj Singh was not a part of it. And even though he did make a comeback later that year in a bi-lateral series against Sri Lanka, he was not in the best of form.

But he was still picked in the 15-member squad for the World Cup because everyone knew what he was capable of.

He had an anonymous start to the World Cup 2011 after not getting a chance to bat as Sehwag and Kohli piled on the runs against Bangladesh.

Source: Eurosport Australia

But the next game against England was when the World Cup truly began for the legend.

Yuvraj showed some form during the match with a quick-fired 50 but his dismissal triggered a collapse that saw India all out for 338 inside 50 overs.

Source: Sporting News

India's bowlers bounced back from a thrashing and managed to tie the game. The next game against South Africa, India lost again due to poor bowling following a batting collapse.

But by the time, India played Ireland, Yuvraj's bowling had become the fore for India. The 'pie-chucker' took 5 wickets against the Irish and then scored a half-century to take India past the target.

Source: ESPNcricinfo

Mind you, unknown to the man himself, Yuvraj Singh was already suffering from cancer at this point.

Source: The Tecake

And it showed in a crucial group stage match against the West Indies. Before the day of the game, Yuvraj started vomiting blood.

Even during the course of the match he was feeling dizzy and kept puking. He was even asked by the umpire Simon Tauffel if he wanted to go off the field.

Source: World in sport

But Yuvi didn't leave the field, not even after his marathon innings.

You can take me to the hospital if I fall or collapse, until then, I am staying.

- Yuvraj Singh

Source: Unbumpf

Yuvraj had to stay on the field because he had made someone a promise. He had to make sure India won.

Before the World Cup, Yuvraj told the media that he was playing this World Cup for 'someone special' who had always stood by him. He might not have revealed it till India reached the final, but we should have guessed who it was.

His promise to Sachin Tendulkar needed to be kept.

Play the tournament for someone you love or respect... Play it for someone you think you owe something to. Make the World Cup part of the debt you have to fulfil.

- Sachin Tendulkar

Source: Rightlog

In the same game, Yuvraj scored 113 out of a grand total of 268 and took two wickets to claim the Man of the Match.

Source: cric revolution

In the quarter-final against Australia, Yuvraj came in to bat at 187-5 with 74 runs still needed to win.

Although India had a lot of overs in which to chase those runs, the team had been going through a multitude of batting collapses at the time. And given that this was Australia, it was absolutely essential Yuvi stayed till the end to see it through.

An hour later, he had scored an unbeaten 57 to take India past the total with two overs to spare and was awarded the Man of the Match for a record-equalling 4th time in the tournament.

Source: Sportskeeda

In the semi-final against Pakistan, Yuvraj might have been dismissed for a golden duck but he took the wickets of Asad Shafiq and Younis Khan in quick succession shifting the momentum of the game and allowing India to win by 29 runs.

Source: Zimbio

Many in India at the time had said that it didn't matter if the team won the World Cup after defeating Pakistan.

But it did, to all those in the blue jersey, it mattered so much!

Yuvraj Singh had been part of the Indian side that lost to Australia in the 2003 World Cup final, like many players in the 2011 team. They knew what it felt like to come this close and see the trophy just slip away.

Source: wisden

So each and every one of those 11 that went on the field that day, played the final at Wankhede like it was their last.

Yuvraj was back to fielding at his old position- the backward point region, a spot on the field usually protected by the best fielder in the team.

At 29 years of age and battling cancer, Yuvraj was far from the best. Or indeed, even his best.

But I guess, nobody gave him the memo. He was flying like a goalkeeper.

Source: catchnews

He didn't have much to do in the final. But his work was already done.

Fate may or may not always be just, but it is almost always poetic. And it gave him the best seat in the house when MS Dhoni smashed one over long on to lift the World Cup after 28 long years.

Source: The Cricket Times

When Yuvraj Singh had made an unlikely comeback to the Indian side for the World Cup 2011 despite a lack of form, Sachin Tendulkar had observed that he was not himself.

At that moment, Tendulkar told him:

When it matters, you will matter the most.

And he did.