LONDON, July 4, 2021 (BSS/AFP) - Novak Djokovic and Roger Federer headline 'Manic Monday' at Wimbledon with the two Grand Slam heavyweights looking to edge closer to a dream title showdown.

World number one Djokovic, chasing a sixth Wimbledon title and record-equalling 20th major, is already halfway to becoming just the third man to complete a calendar Grand Slam.

The Serb faces Cristian Garin of Chile while eight-time champion Federer takes on Italy's Lorenzo Sonego.

Chilean 17th seed Cristian Garin had never previously won a main draw match at the tournament before this year.

However, the 25-year-old from Santiago is in the last 16 of a major for the second consecutive Grand Slam.

"It feels amazing. I didn't play a grass tournament before Wimbledon, so I was a bit out of rhythm and without any matches on grass," said Garin who lost his only clash with Djokovic at the ATP Cup in 2002.

"My last match on this surface was here at Wimbledon in 2019."

Federer, just five weeks shy of his 40th birthday, is in the Wimbledon last 16 for the 18th time.

In all, it will be his 69th appearance in the fourth round of a Slam but he was quick to salute Djokovic's
 achievements.

"It's just very, very impressive to see what he's doing this year," said Federer whose third round win over Cameron Norrie gave him the 1,250th victory of his career.

Second seed Daniil Medvedev staged a stunning comeback from two sets down for the first time in his career to beat 2017 runner-up Marin Cilic and make the fourth round for the first time.

Medvedev faces Polish 14th seed Hubert Hurkacz.

Sebastian Korda, whose father Petr made the quarter-finals in 1998, celebrates his 21st birthday on Monday.

He can reach the quarter-finals of a Slam for the first time by beating Russian 25th seed Karen Khachanov.

- Double for Italy -

Denis Shapovalov, the Canadian 10th seed who put out two-time winner Andy Murray in the last round, faces Spain's Roberto Bautista Agut, a semi-finalist in 2019.

Meanwhile, Italy will have two men in the last 16 for just the third time and first time since 1955.

While Sonego faces Federer, seventh seed Matteo Berrettini faces Ilya Ivashka of Belarus, the 27-year-old world number 79 who had only previously won one match at a major before this Wimbledon.

Women's world number one Ashleigh Barty, trying to win the title 50 years on from fellow indigenous Australian Evonne Goolagong Cawley's maiden crown, tackles French Open winner Barbora Krejcikova.

The only British player left in the singles draw is 18-year-old Emma Raducanu who has defied her ranking of 338 to make the second week where she meets Australia's Ajla Tomljanovic.

Germany's Angelique Kerber, the only former champion left in the women's event, takes on Coco Gauff.

Big-hitting will be a feature of the lower half of the women's last 16 on Monday.

Belarus second seed Aryna Sabalenka faces 18th seeded Elena Rybakina.

Sabalenka, yet to make a quarter-final of a Slam had 21 aces over three rounds, one fewer than Russian-born Rybakina.

Former world number one Karolina Pliskova, the eighth-seeded Czech has also fired 22 aces and she faces unseeded Russian Liudmila Samsonova.

Samsonova, ranked 65, has made the most of her wild card to register her best ever performance at a Slam.

Having won the Berlin grass court tournament as a qualifier in the run-up to Wimbledon, the 22-year-old is on a 10-match win streak.

Former French Open champion Iga Swiatek, the seventh seed who had won just one match in grass on the main tour before Wimbledon, takes on Tunisia's Ons Jabeur, the 21st seed.

Jabeur can become the first Arab woman to reach the Wimbledon quarter-finals with victory.