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That birdie putt on the ninth was pretty timely for Rory McIlroy.

Just as the field was beginning to gather, he inched to one under for his round and stretched that lead to an ever more unassailable distance.

So what do we reckon?

Rory on the march? Or will it all unravel again?

Thumbs please.

Wonder what Bryson DeChambeau is thinking?

He's not got it going at all today and four shots behind Rory McIlroy is a mountain with nine holes left.

His ball is also away and chugging down the 10th fairway.

He likes it.

Rory McIlroy is safely away at the 10th hole.

Solid, confident start to the second nine.

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All the field have played the first nine at Augusta National, Rory McIlroy had the lead, then lost it, now is in command.

McIlroy is chasing Grand Slam glory but there are plenty chasing him - Bryson DeChambeau is struggling but Justin Rose, Ludvig Aberg and Patrick Reed are flying.

Welcome to the back nine on a Masters Sunday folks, where anything can happen, this will be epic....

The 10th hole.

Scene of such misery for Rory McIlroy back in 2011.

The triple bogey on that day cost him the lead - and caused him to totally unravel.

He could put that to bed right here right now.

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These putts are not dropping for Bryson DeChambeau.

He's slipped four back.

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It is indeed!

We've had no change in the scores for this duo since the third hole.

Boring, right?

Could that be about to change...

The putts are certainly dropping for Justin Rose now!

He cut a frustrated figure on the greens yesterday, but after safely boarding the surface at the treacherous par-three 12th, he backs up his brilliant birdie on the 11th with another.

He's joint-second now and is certainly not giving up on a second major title.

Tremendous approach from Bryson DeChambeau into the ninth green. Finally, he's got one to land nice and close.

Rory McIlroy joins him on the dance floor at a similar distance from the pin.

The two balls make an isosceles triangle with the flagstick.

If you can remember your primary school maths, that's a perfect visual aid for you.

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Ludvig Aberg finally gets one of those birdie putts to drop to join Bryson DeChambeau on nine under.

He's been knocking on the door all day and now last year's runner-up on his debut is right back at the sharp end.

Patrick Reed is on a real tear now as he sticks in a birdie putt on nine to make it four in a row to leap up the leaderboard to eight under.

The 2018 Masters champion could make a serious move now as we head into the second nine.

It can be quite confusing watching these tee shots as they fling either left or right and seem destined for the trees.

Not so for Rory McIlroy at the ninth as his ball clears those tall trunks by some distance and trundles down the fairway.

Bryson DeChambeau drive is much straighter. He'll leave it in the corner of the dogleg and in prime position to attack the green.

That's it Rosie! He sinks a superb birdie putt on the 11th, across the green to the delight of the huge gallery situated on Amen Corner.

The 11th strikes fear into even the most confident golfer so Rose has definitely gained one against the head there.

His third birdie in five holes and he's now four back of McIlroy.

The smile on Bryson DeChambeau's face appears a wry one as he leaves the seventh green to the shouts of: "Come on, Rory!"

He's not been able to get anything going to fire up the patrons - and that's usually petrol to his engine.

Ten holes left to fan the flames.

Excellent effort from Rory McIlroy from 27 feet as he gives himself a tap-in par.

He's not taking advantage of the par fives either - but given the current leaderboard, that suits him.

Solid from DeChambeau after his miss, confidently saving his par.

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Superb eagle on the 13th for Sungjae Im, who was a distant joint runner-up to Dustin Johnson here in Covid-impacted Masters of 2020.

The South Korean is up to seven under - he could definitely sell that eagle to one of the last groups for a few quid though.

Bryson DeChambeau is banking on some serious break here at the eighth green.

He sticks his hands on hips though as he overreads and it carries on past the hole four feet.

The big-hitting Californian is not taking advantage of the par fives yet.

Scottie Scheffler is a roll or two away from nailing an absolute monster of a putt on 10, but has to settle for a par.

At seven under Scheffler has to try and engineer something special and hole a few of these bombs to try and give the leader something to think about.

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Crackerjack of an approach from Jason Day on the ninth as he finds just the right shelf on the green to take his ball back down into gimme range (if there is such a thing at Augusta on Sunday).

There's certainly nothing doing for Ludvig Aberg again as he fails to sink another birdie putt - just an average putting day would have him so much closer.