West Indies v Pakistan, Edgbaston
West Indies won by one wicket
This was a crucial match for both teams. With a win here, Pakistan would have been in the race to qualify for the semi-finals, because they went on to make 330 against Sri Lanka in their next game, which boosted scoring rate. If there had been a three-way tie for points, West Indies might have lost out. And even if they made it to the semis, West Indies might have faced the stronger England there instead of New Zealand. Since this match was right in the middle of the tournament, the whole inaugural World Cup might have taken a different turn.
England v Pakistan, Headingley
England won by 14 runs
Both England and Pakistan had already qualified for the semis, so this match only had significance with regard to group placings - the winner would face New Zealand instead of West Indies in the semi-final.
India v Zimbabwe, Tunbridge Wells
India won by 31 runs
This is, arguably, the most significant ODI match ever played by India. They slumped to 9 for 4, 17 for 5 and 78 for 7 before recovering to 266 for 8 thanks to the second-greatest ODI innings of all time, a magnificent 175 not out by Kapil Dev. This win started India's march towards their magnificent title triumph a week later. If India had lost to Zimbabwe, they might not have qualified for the knockouts, or they might have met West Indies in the semi-finals.
India v Australia, Chennai
Australia won by one run
The fact that Australia ultimately went on to win this World Cup makes their narrow victory over India in their opening game significant, especially since they lost the next encounter between the two teams in the tournament. Geoff Marsh's pedestrian but invaluable hundred helped Australia post a very good total of 270. India were sitting comfortably at 207 for 2 around the 35th over and an easy win seemed likely when Craig McDermott induced a panic with his four wickets.
England v Pakistan, Adelaide
Pakistan arrived in Adelaide needing a win, having won a match and lost one. That looked unlikely when they were bowled out for 74, their lowest World Cup total to date, and they were lucky that rain washed out the game and gave them a valuable one point. It is difficult to conjecture what would have happened if Pakistan had lost in Adelaide. Since they lost their next two matches, they would have been sitting with one win out of five and might not have qualified for the knockouts.
Sri Lanka v India, semi-final, Calcutta
Sri Lanka won by default
After India beat Pakistan in the quarter-final in Bangalore, they were favourites to win the title. In the semi-final at Eden Gardens, Sri Lanka batted first and fell to 35 for 3 - their top three batsmen collectively scoring only two runs in the innings. The No. 4, Aravinda de Silva, attacked Anil Kumble and Venkatesh Prasad and eventually Sri Lanka reached 251, which was hardly a demanding target for the star-studded Indian line-up. Sachin Tendulkar played magnificently and India were comfortable at 98 for 1 when Jayasuriya, who had failed with the bat, struck with the ball. He triggered a collapse by dismissing Tendulkar and Sanjay Manjrekar. India lost seven wickets for 22 runs and needed another 132 to win with two wickets in hand. At that point the Calcutta spectators decided to show their displeasure by throwing bottles on the field and setting fire to the seating in the stands. The match was called off amid mayhem and Sri Lanka were declared deserving winners. They went on to win the World Cup four days later.
Australia v South Africa, Headingley
Australia won by five wickets
If Australia hadn't won this Super Six game against South Africa, then, following the tied semi-final at Edgbaston, it would have been South Africa going into the final. A beautifully paced hundred from Herschelle Gibbs and supporting acts by Daryll Cullinan, Jonty Rhodes and Lance Klusener took South Africa to a potentially match-winning 271. Australia lost three quick wickets after which Steve Waugh and Ricky Ponting added a match-winning 126 together. Waugh played one of the greatest World Cup innings, remaining unbeaten on 120 to take Australia into the semis with two balls to spare.
Australia v Sri Lanka, semi-final, Port Elizabeth
Australia won by 48 runs (D-L method)
Australia were unbeaten in the 2003 World Cup, and in the group stage, except for a close match against England, they won each game quite comfortably. However, this was not a high-scoring World Cup and the bowlers had their days under the African sun. In the semi-final, despite a composed 91 from Andrew Symonds, Australia only managed a sub-par 212 for 7. But Sri Lanka struggled against Australia's top-quality pace attack and were reduced to 76 for 7. Kumar Sangakkara and Chaminda Vaas' 47-run stand only delayed the inevitable. Rain came down in torrents to end the one-sided contest and give Australia an easy D-L win.
Bangladesh v South Africa, Providence
Bangladesh won by 67 runs
After their heartbreaks in 1999 and 2003, South Africa came into the 2007 World Cup as strong contenders for the title. They had lost only one match - to Australia - when they met Bangladesh, still considered "minnows", in the Super Eights. Mohammad Ashraful's magnificent 87 off 83 balls took Bangladesh to 251 for 8, which should have been easy enough for South Africa's strong batting line-up. However, the Bangladesh spinners restricted the free-scoring South African batsmen and earned a 67-run win. The result changed the dynamic of the tournament significantly - South Africa now had to meet a rampaging Australia in the semi-final instead of in the final as had been expected.
India v Pakistan, semi-final, Mohali
India won by 29 runs
I have selected this match as a tide-turning one for India because, in many ways, it was a more difficult match than the final for them. Tendulkar played, arguably, the worst innings of his career but also perhaps his most valuable one. He scratched around for nearly three hours and was dropped no fewer than four times during his 115-ball 85, which took India to a competitive 260 for 9. There was no big innings from Pakistan, and though nearly all the top-order batsmen got starts, their highest score was 56 (by Misbah-ul-Haq) and their biggest partnership was 44 (between openers Kamran Akmal and Mohammad Hafeez). They fell 29 runs short. The five Indian bowlers took two wickets each. It was a scrappy match but a big win for India.
New Zealand v Australia, Auckland
New Zealand won by one wicket
In a World Cup Australia dominated and won, I have picked a match they lost. The reason is simple: this defeat stung them hard. After this game, Australia did not put a foot wrong and won six successive matches in commanding fashion to seal their fifth title.
A look at the current World Cup
Anantha Narayanan has written for ESPNcricinfo and CastrolCricket and worked with a number of companies on their cricket performance ratings-related systems