The World No.1 is up next on Suzanne Lenglen! Naomi Osaka has had two stern tests so far at Roland Garros - will she have an easier time aginst Katerina Siniakova?

Of course it ends with an Osaka unforced error - this time a long forehand. It's a total of 38 for the day and Naomi's hopes of winning a third straight Grand Slam are over. What an upset!

Osaka's errors look like they are going to cost her. Now it's the serve that's disintegrating rather than the ground strokes and she is now a double break down in the second set and Siniakova will serve for the match.

Osaka attacks, attacks and attacks again. Winners are flying off her racquet but so are unforced errors. She pushes Siniakova all the way but finds the net, then pushes a forehand wide and can't force the break back.

Osaka is in real, real trouble now. She's a break down and Siniakova is on the verge of a brilliant victory. Osaka's missed all seven of her break point chances so far but she needs to conjure up something soon.

That was a stern examination from Osaka. Another unforced error brings Siniakova break point but the World No.1 recovers to grind out a hold.

Osaka has come out swinging at the start of the second set, holding to love then pushing Siniakova to deuce. The Czech holds firm and grinds out a hold. You still feel that this match is on Osaka's racquet - it's just a case of whether she can cut out the unforced errors.

Game and first set Siniakova! Osaka squanders four chances to break back but Siniakova converts her second set point and takes the first set.

Osaka has gone the distance in both of her Roland Garros matches so far but and she'll have to do so again to reach the round of 16.

After trading routine holds, Siniakova has the first break of the match and will serve for the first set!

Osaka sends a forehand into the tramlines when facing break point and may live to rue not capitalising on the pressure she put on the Czech.

Osaka finally gets a couple of chances to break. On the first one she slips as she tries to chase down a drop shot, on the second, she sends a return well long. How much longer can Osaka probe and how much longer can Siniakova withstand the pressure?

Osaka is looking untroubled thus far on serve. She seals this game with a backhand pass that snuck over the net.

Osaka once again lets a two-point lead slip, first through a long return when she looked to punish a tame second serve, then through a drop shot. Siniakova holds.

Osaka sees her 30-0 lead vanish thanks to some added aggression from Siniakova but it doesn't cost her as a volley and a clean winner help her hold.

Siniakova is forced to dig deep in her very first service game, seeing off a break point as Osaka looked to get on the front foot at every available opportunity.

Naomi Osaka makes a fine start to the match, holding to 15. There was one forehand down the line which showed us that she could be in the mood today in there.