It only took the preliminary stages of the men's World Cup to highlight one advantage the T20 format has over Test cricket: the greater likelihood of an upset. Bangladesh lost to Scotland, and Namibia knocked Ireland out of the Super 12s. It's dangerous mingling with the minnows.

In Test cricket, in some matches it might look like a major upset is about to occur, but it rarely comes to pass. Ireland appeared on the verge of the upset of the century when they dismantled the England batting line-up for 85 at Lord's in 2019. But despite holding a first-innings lead of 122, the Irish batting folded like a paper plane in the second innings to be all out for a paltry 38.

We've just had another reminder that major upsets occur regularly in T20 World Cup tournaments. In 2009 at Lord's, England suffered a calamitous defeat at the hands of Netherlands, which led to the home side missing the semi-finals.

There have been other upsets, not of the same magnitude as England's loss, but still embarrassing for the major nation. Then there are the exciting near-misses, where the less-fancied team appears to be on track to upsetting a major nation but eventually normality prevails.

One such occasion, also in 2009, was an enthralling battle between Sri Lanka and Ireland at Lord's. The fighting Irish looked to be in position to upset Sri Lanka when they held them to 144. The possibility of an upset came into sharper focus when Ireland compiled a productive opening partnership of 59 after just nine overs.

I was sitting in the Lord's press box in a group of animated Irish journalists. "Should be a big party tonight," I said, "if Ireland win." Without even turning his head, one journalist replied with typical Irish humour: "Regardless."

Of the minor countries who have performed reasonably regularly in T20 World Cups, Netherlands and Scotland have won over a third of their matches. In general this is a result of them winning games they were expected to win against other minor nations.

The two latest nations to acquire Test status - Afghanistan and Ireland - have performed creditably, respectively winning 35% and 22% of their T20 World Cup matches, while the often-threatening-but-rarely-producing Bangladesh are at 25%.

The inclusion of minor cricket nations - there were five in the current tournament - can lead to some club-standard cricket. Nevertheless, it's worthwhile encouraging these countries through the T20 format. It's a bit like the early rounds of English football's FA Cup, where occasionally the part-timers upset the highly paid professionals and a township celebrates wildly. However, when the dust settles and the ambition has been doused, it will be four major nations who survive the cut and thrust to reach the semi-finals of this year's World Cup.

In a format where a quick-fire 20 that includes a couple of biffed sixes, or a brief but accurate two-over spell, can change the course of a match, predicting semi-finalists is fraught with danger. Adding to the uncertainty, this tournament is being played in a part of the world where the conditions are unfamiliar to many of the major teams.

Logic would say that the venue favours the highly unpredictable Pakistan, who for most of the previous decade used the UAE as their "home" turf. Also, players who participated in the second half of the rearranged IPL will benefit from the tournament's shift to the UAE and that makes India a big beneficiary.

In Group 2, the most likely semi-finalists are India and Pakistan, with the biggest danger to them being New Zealand. Group 1 - where Australia, England, South Africa and West Indies all reside - is much more difficult to predict. Using the pin-the-tail-on-the-donkey method, I favour England and West Indies to qualify from this group, but I do so with little conviction. And that's the beauty of the T20 World Cup - it's a lottery.

Former Australia captain Ian Chappell is a columnist