What a difference a year makes.

Twelve months ago, Tommy Fleetwood completed his transformation to elite level with a runner-up finish in the WGC-Mexico Championship, forcing Dustin Johnson to pull out all the stops as he won on his first start as the world's top-ranked player.

Johnson was his usual self - all carefree brilliance, what will be will be - but as mistakes crept in on the back-nine of what had looked like another victory parade, perhaps he was fortunate that Jon Rahm and Justin Thomas were both contending for the first time at this level. Thomas made some impatient mistakes early on Sunday while Rahm three-putted 16 and 17 to miss out by two. Handed the same opening again, few would expect the same outcome.

In the end it was left to Fleetwood, a 200/1 chance at the start of the week, to ask the biggest question of Johnson with a 38-foot birdie on the final hole before the reigning US Open champ played what he called his best shot of the week, an approach from sand to inside 20 feet enough to ensure that he would add a fourth World Golf Championship title to his collection, before collecting a fifth soon after.

At the time, Johnson appeared unbeatable. After all, he'd managed to win this event despite starting it with a three-wood through the green and out of bounds at the par-four opening hole, which resulted in double, and despite missing no fewer than 16 putts from inside 10 feet during the week.

Both those facts tell us a little about Club de Golf Chapultepec, a par 71 which measures over 7,300 yards but plays significantly shorter due to the altitude factor here on the outskirts of Mexico City. Most players, when interviewed, referred to altitude and to small, sloped greens as the two biggest challenges.

Ross Fisher, who finished third, said the ball was travelling some 20 per cent further than usual while Rory McIlroy boasted of walloping his eight-iron an eye-watering 210 yards. DJ's three-wood to the opener on Thursday carried 330, while short-hitting Roberto Castro struck a drive beyond 400 yards which I would wager he'd never done before.

As for the greens, Phil Mickelson labelled them the golf course's "greatest challenge" and perhaps they were too hard for anyone to truly master. Ultimately, the final leaderboard was a list of elite ball-strikers and neither Johnson nor Fleetwood putted particularly well. Eight of the top 10 could be called long, world-class drivers of the ball, too, although Johnson said he barely had to reach for the big stick and relied instead on his trusty two-iron.

Fleetwood was among my selections for the event last year in the vague hope that the challenge would suit European players, especially those with form in the Swiss Alps at Crans-sur-Sierre, and that angle was supported when the man himself described Chapultepec as "a very European course" en route to second place.

All told, 11 of the top 22 finishers were European and another was European Tour stalwart Fabrizio Zanotti, who bagged 12th place for by far his best performance in elite company. The Paraguayan went on to finish third at Crans later in the year, a course at which top-10 finishers Fleetwood, Fisher and Tyrrell Hatton have thrived, so however tenuous it may seem, the Omega European Masters might be a decent guide.

In the US, the eye is drawn to the Barracuda Championship played up in the mountains in Reno, except for the fact that it is low grade by nature, while the 2014 BMW Championship won by Billy Horschel may in time prove a decent pointer. It was an event played at altitude in Colorado and dominated by ball-strikers, with the likes of Sergio Garcia and Rory McIlroy close behind Horschel and Bubba Watson.

Garcia, who owns a home in Crans, is tempting enough at 28/1 having been 12th here last year and there's a case for altitude-winning, big-hitting Gary Woodland at around twice that price, but my idea of the best bet is in fact Paul Casey.

Those are not words I type often, but 40/1 about the world number 17 looks a solid option on this occasion after a slightly underwhelming performance at Riviera last time saw his odds eased slightly.

Prior to that, Casey had started the season with back-to-back top-10 finishes and he looks exactly the right type of player for this test based on last year's leaderboard, one he worked his way up with rounds of 67 and 66 over the weekend - one better than DJ, one worse than Fleetwood, and third in the field.