The stats don’t lie. Those big, horizontal blocks depicting the toughest holes at Royal Troon were gathered together and Graeme McDowell summed it up best when he said turning onto the back nine felt like “walking onto a different golf course”.

All week Royal Troon has been dressed up as a venue that plays as a game of two halves. Getting all the superfluous analogies out of the way early, there is still some truth in this observation and the sternest test begins the moment players reach the farthest point of the course.

Troon is the classic links layout; nine holes south along the coast before turning for home, and with the exception of the Postage Stamp eighth and par four 12th, the holes on each nine run in the same direction.

The general consensus has been that the prevailing north westerly adds to the difficulty of Troon’s back nine, but that notion didn’t stack up for the same holes proved just as treacherous when the wind shifted in the opposite direction for yesterday’s second round.

A beast

The biggest blue stack of all on the R&A’s stats page was housed on the 482-yard par four 11th called The Railway.

A quick recce to this part of the property and it’s easy to see why it sends chills down the spines of the game’s best players.

It's a beast of a hole – from start to finish. There's a reason why Jack Nicklaus picked it out as the most difficult hole on The Open rota.

For starters, the championship tee is tucked away from civilisation and insists on players firing over a sea of gorse to a narrow fairway that runs diagonally against the eye. Anything left and it’s curtains with yet more gorse, slide it right and your ball might well be on the rail commute to Glasgow. Oh, and you need to hit it 280 to reach the fairway.

It doesn’t get any easier further up the hole as the fairway bottlenecks to the green with the boundary wall just a couple of paces off the putting surface. If this was the music charts, then the 11th dropped straight in at number one – playing over 4.5 against par – and this stubborn one will be hard to shift.

Dustin Johnson was one of many players to succumb to the 11th when he coughed up a double bogey six to stall any momentum after reaching the turn in two-under.

“It was especially tough coming down the back nine, those holes are tough whether they’re playing into the wind or downwind,” said the US Open champion, who managed to regain lost ground with three birdies on the spin from the 15th to finish on two-under.

The 11th is flanked by the 10th and 12th, the third and sixth most difficult holes respectively. And just when you think there might be some respite, the new-look 15th emerges as the second toughest hole of the week so far. After a makeover where the first part of the fairway was rerouted, the 15th is now the longest par four on the course at 499-yards with a slightly blind tee shot and new bunkering to contend with.

More birdies

On the positive side of the ledger, it comes as little surprise to find three par fives the easier of the pickings. The 555-yard fourth is fodder, playing an average 4.7 and is closely followed by the 16th and sixth.

It’s interesting to note Postage Stamp (the 123-yard, par three eighth) has had its victims over the first two days, but overall has offered up more birdies than bogeys and is tucked in behind the three par fives as the fourth easiest hole.

Stats can be manipulated to suit but there is no denying the back nine is all about damage limitation and by far the sterner side of the course, at one stage registering eight of the most difficult holes. A point not wasted on McDowell.

“There is no doubt that this links golf course is quirky on a lot of levels. The two nines scenario is amazing. You get to the 10th tee and it’s literally like you’re walking onto a different golf course. The shape of the greens change. You get some very difficult tee shots and you get some length all of a sudden after a very benign first nine holes,” said McDowell, who was battling to make the cut after finishing on four-over.

His card also slotted neatly into the two nines template for he turned in four-under 32, only to give it all back by coming home in four-over 39.

“In and around the greens is very unusual as well. It’s actually not very linksy,” added McDowell. “The ball rolls off and it runs in the semi-rough where you can get your lob wedge on it. It’s quite unusual from my point of view and obviously the back nine is a brutal nine of golf.”