Iga Swiatek stayed on track for a successful defence of her French Open title with victory over Ukrainian teenager Marta Kostyuk to reach the quarter-finals.

A week after her 20th birthday, Swiatek is in the unexpected position of being the experienced player in the field in terms of grand slam success having won her maiden title here last year.

The Pole's 6-3 6-4 victory over 18-year-old Kostyuk extended her winning run at Roland Garros to 11 straight matches and 22 sets – not quite Rafael Nadal territory but supremely impressive for such a young player.

Swiatek is not just the only player left in the women’s draw who has won a slam title but the only one who has gone beyond the quarter-finals, so it is no surprise she is a heavy favourite.

She was certainly pushed by Kostyuk, who reached the third round of the Australian Open aged only 15 and is beginning to string results together.

It was nip and tuck through the first seven games, with Kostyuk using her defensive skills to match her opponent shot for shot, but in the end Swiatek’s variety and poise helped her move clear.

Elsewhere Coco Gauff broke new ground by reaching the quarter-finals.

The 17-year-old American caused a sensation when she made the fourth round at Wimbledon two years ago and repeated the feat at the Australian Open in 2020.

Now she has gone one better and, if her form in a 6-3 6-1 victory over Ons Jabeur is anything to go by, she is a legitimate contender for the title.

Coco Gauff breezes into quarter-final in Rolland Garros

Gauff has been in excellent form on the European clay, winning a title in Parma and rising to a career-high ranking of 25 in the world.

She was dominant in all areas against Tunisian Jabeur but particularly on serve, dropping just nine points on her own delivery in the match to cruise into the last eight.

Gauff, who won the junior title at Roland Garros three years ago, is yet to drop a set in singles.

In the last eight, the teenager will face another first-time slam quarter-finalist - in singles at least - in Czech Barbora Krejcikova.

The 25-year-old was even more dominant, beating former finalist Sloane Stephens 6-2 6-0.

Stephens had looked in good form but she made a slow start and never recovered, hitting 26 unforced errors compared to just nine winners.

Krejcikova is better known as a doubles player but she has been climbing the singles ladder and is now on a nine-match winning run after claiming a WTA title in Strasbourg.