First things first for Putintseva, she must win her service games.

It starts well as she leads 30-0 before Muguruza claws her way back to 30-30 with a scamper forward to meet another drop-shot. Brilliant!

She lunges to scoop a forehand winner past the Kazakh - good feet for a big woman - following that up with another winner.

Break point... and Putintseva buckles.

Dom Inglot
Great Britain Davis Cup player on BBC Radio 5 live sports extra

Muguruza is trying to match the energy levels that Putintseva brings to the court but I'm not sure anyone can match Putintseva's levels.

That was a good solid hold and now she will want to apply the pressure to Putintseva's serve.

If you had to have a favourite tennis umpire (niche, I know) then it would have to be Kader Nouni. Not only does he sound like Barry White, but he leaps off his seat and down on to the red stuff with the speed of Usain Bolt.

He is needed twice to inspect ball marks after calls are questioned by Putintseva, both are ruled to be correct and Muguruza goes on to reassert her authority with a hold to 15.

Winning a break is one thing, consolidating it is another. Especially in this match.

But Yulia Putintseva manages to do exactly that, a routine hold to love heaping the pressure back on to the defending champion.

Just as Dom Inglot says that, Putintseva shows us her battling qualities.

Two break points for the Kazakh. One slips away when a backhand goes long. The second? The point is replayed when Putinteva challenges, only for her to blow that reprieve with a soft drop-shot that hit the tape.

Racket meets clay, followed by a slow turn to her box (Eric Cantona style) with dramatic placing of hands on hips. If looks could kill...

But she recovers to rack up another break point in deuce, forcing Muguruza into an error, and clawing back one of those breaks.

Dom Inglot
Great Britain Davis Cup player on BBC Radio 5 live sports extra

Putintseva is a feisty character and won't give up. I think I saw one of the biggest fist-pumps in recent history from her at Wimbledon last year.

Image source, Getty Images

Yulia Putintseva is certainly an emotional character - and it is great to watch. She fist-pumps wildly after a forehand winner sticks her 15-0 ahead but her mood darkens quickly as two unforced errors help set up two more break points for Muguruza.

The line-judge's seat behind the Kazakh feels the force of her right boot. Releasing some anger doesn't help her, however, Muguruza's power is just too much for her.

The Spanish fourth seed steps inside the court again, whacking down a forehand winner to move halfway to the second set.

Muguruza takes a moment to compose herself ahead of deuce - too long as it turns out. She receives a warning from husky-voiced umpire Kader Nouni for taking too much time, but doesn't let it affect her too much as she pins Putintseva to the baseline before the Kazakh goes long.

The Muguruza rollercoaster takes another dip as she palms a net volley into the mesh, but then climbs again with a couple more impressive points to hold.

Garbine Muguruza looks to have too much power for Yulia Putintseva, but one thing you can count on from the Kazakh is plenty of fighting spirit.

After more success with the drop-shot, she digs in to stay in a long baseline rally and when Muguruza blinks first, she forces deuce...

Image source, Reuters

Bad news for David Goffin.

The Belgian 10th seed is out of Roland Garros after a nasty fall in his match against Argentina's Horacio Zeballos over on Lenglen.

Goffin was leading 5-4 in the first set when he crashed into the court covers and the advertsing hoardings. Ouch.

It looked like an ankle injury and he was not fit enough to carry on. Zeballos looks rather upset as he apologetically waves to the crowd following his enforced win.

Putintseva isn't happy and very nearly smashes her racquet twice, bashing it into the clay after failing to take chances to win this game.

And a backhand down the line secures the break for Muguruza.

Putintseva continues to struggle on her serve and Muguruza is dominating the rallies, hitting with power, and making her opponent scurry around.

But Putintseva scurries well and puts in two under-spinning drop shots to halt Muguruza's progress and we're into deuce...

Russell Fuller
BBC tennis correspondent at Roland Garros

It has been a bit of a struggle but Muguruza seems to have the beating of Putintseva and it doesn't feel like a fair contest because of Muguruza's power - when she's on her game.

Image source, Getty Images

Job done...eventually. Garbine Muguruza's performance has not been pretty, and not always effective, but she has finally done enough to edge past Yulia Putintseva.

The Spanish fourth seed's power clinches an opening set which had six breaks of serve.

Piers Newbery
BBC Sport at Roland Garros

The match has got into bit of a rhythm now. Putintseva is struggling to get enough on her serve and Muguruza is finding it suits her game. It's the rallying points where Muguruza is showing some weakness.

Right back at you!

There are more ups and downs in Garbine Muguruza's game than the Big One at Blackpool Pleasure Beach.

Putintseva lets anger get the better of her, slamming her racket into the red stuff after a double fault and forehand unforced error gives Muguruza two break points.

She only needs one. And the opener is back in her hands.

Russell Fuller
BBC tennis correspondent at Roland Garros

Muguruza playing well in patches but it is very patchy.

Image source, Getty Images

Putintseva finally breaks Muguruza's serve again - at the fourth time of asking in this game - after the Spaniard plants a backhand volley into the net from close range and follows that up with a meaty forehand that just misses the baseline chalk.

As you were...

Muguruza saves one with a crackerjack of a forehand winner, and then Putintseva lets her off the hook with a rogue forehand that she knows she needed to make.

A exasparated sigh and look up to the clear Paris sky sums up the Kazakh's feelings. She knows...

Putintseva regains her focus to execute a googly of a drop-shot that spins out Muguruza's reach, setting up another break point...

A clenched fist from Yulia Putintseva towards her box tells you that she is pretty pleased. Not surprising seeing as she leads 30-0 on Muguruza's serve.

Muguruza hits back with a booming first serve which cannot be controlled by the Kazakh, only for an unforced error from the Spaniard to cough two break points...