London -Eight-time Wimbledon champion Roger Federer overcame a first set scare to reach the second round on Tuesday beating South African debutant Lloyd Harris 3-6, 6-1, 6-2, 6-2.
Federer, whose great rival Rafael Nadal was also in action against Japanese qualifier Yuichi Sugita, took time to get going and was helped by his opponent suffering a calf problem midway through the match.
"I struggled early on, my legs were frozen and the ball was not going where I wanted it to," said Federer.
"He was hitting big and things were going quickly. I was nervous for a set and a half.
"So it took a good effort from me. Lloyd played a good match."
If Nadal comes through, he will renew his bitter rivalry with Nick Kyrgios after the combustible Australian claimed a 7-6 (7/4), 3-6, 7-6 (12/10), 0-6, 6-1 win over countryman Jordan Thompson.
Kyrgios, who stunned Nadal as a 144-ranked wildcard on his tournament debut in 2014, put in a typically raucous and charismatic display on Court 3 where he fired 23 aces and 63 winners.
However, while he progressed another of the top 10 seeds fell by the wayside -- two-time French Open champion Dominic Thiem's lack of ease on grass being exposed by veteran American serve and volleyer Sam Querrey.
Querrey, a Wimbledon semi-finalist in 2017, prevailed 6-7 (4/7), 7-6 (7/1), 6-3, 6-0.
"There's still things which are not easy," said Thiem.
"I mean, last year and this year together I played four grass court matches, which is not a lot at all.
"All the clay court season it takes a lot out of me," added the 25-year-old Austrian.
Women's world number one Ashleigh Barty and defending champion Angelique Kerber avoided the fate of second seed Naomi Osaka and came through their first round clashes safely.
Barty beat China's Zheng Saisai 6-4, 6-2 while Kerber, the fourth seed, beat fellow German Tatjana Maria 6-4, 6-3.
Whilst Barty did not have it all her own way in the first set being pegged back to 4-4 after leading 3-0 she had little trouble after winning the first set.
"The first round is always very tough and it took a little time to get used to the court," said Barty.
"It definitely took some time to adjust."
Barty, who is bidding to become the first woman since Serena Williams in 2015 to win both the French Open and Wimbledon in the same season, drew on the film The Lion King to describe how she felt leading into the match.
"Kind of came into it thinking kind of like hakuna matata (Swahili for no trouble and a title of a song in the film), just relax and go for it," said the 23-year-old.
Barty plays tricky Belgian Alison Van Uytvanck, who knocked out then defending champion Garbine Muguruza last year in the second round, for a place in the last 32.
"It will be an exceptional challenge and it will be important for me to be strong on my serve," she said.
Barty may have not been nervous but Kerber, who came into the tournament on the back of being the beaten finalist at Eastbourne last Saturday, confessed to being so before she walked out onto Centre Court.
Her game appeared to reflect that as she lost her serve on several occasions but in the end won comfortably enough.
"This is the tournament of the year where you really would like to play your best tennis," said Kerber.
"I think it was a little bit different, but the nerves and everything are the same.
"Doesn't matter which Centre Court you are coming back as the defending champion."
Meanwhile, Kate, the Duchess of Cambridge, left the plush confines of the Royal Box at Wimbledon to watch a British wildcard competing on the lowly outside courts.
In a rare move for a member of the royal family visiting the All England Club, Kate took her place in among the 318 regular seats on Court 14 to watch Harriet Dart take on Christina McHale.
Wimbledon results on Tuesday (x denotes seeding):
Sam Querrey (USA) bt Dominic Thiem (AUT x5) 6-7 (4/7), 7-6 (7/1), 6-3, 6-0
Andrey Rublev (RUS) bt Christian Garín (CHI) 4-6, 6-4, 7-5, 6-4
John Millman (AUS) bt Hugo Dellien (BOL) 6-2, 6-3, 6-4
Gilles Simon (FRA x20) bt Salvatore Caruso (ITA) 7-6 (9/7), 6-3, 6-2
Tennys Sandgren (USA) bt Yasutaka Uchiyama (JPN) 3-6, 6-2, 6-4, 6-3
Fabio Fognini (ITA x12) bt Frances Tiafoe (USA) 5-7, 6-4, 6-3, 4-6, 6-4
Dan Evans (GBR) bt Federico Del Bonis (ARG) 6-3, 7-6 (7/5), 6-3
Nikoloz Basilashvili (GEO x18) bt James Ward (GBR) 2-6, 4-6, 6-4, 6-4, 8-6
Ricardas Berankis (LTU) bt Denis Shapovalov (CAN x29) 7-6 (7/0), 6-4, 6-3
Jo-Wilfried Tsonga (FRA) bt Bernard Tomic (AUS) 6-2, 6-1, 6-4
Nick Kyrgios (AUS) bt Jordan Thompson (AUS) 7-6 (7/4), 3-6, 7-6 (12/10), 0-6, 6-1
Rafael Nadal (ESP x3) bt Yuichi Sugita (JPN) 6-3, 6-1, 6-3
Kei Nishikori (JPN x8) bt Thiago Monteiro (BRA) 6-4, 7-6 (7/3), 6-4
Cameron Norrie (GBR) bt Denis Istomin (UZB) 6-2, 6-4, 6-4
Steve Johnson (USA) bt Albert Ramos (ESP) 6-4, 6-2, 6-3
Alex De Minaur (AUS x25) bt Marco Cecchinato (ITA) 6-0, 6-4, 7-6 (7/5)
Jan-Lennard Struff (GER x33) bt Radu Albot (MDA) 6-4, 6-3, 6-2
Taylor Fritz (USA) bt Tomas Berdych (CZE) 6-4, 6-4, 6-3
Mikhail Kukushkin (KAZ) bt Pablo Andújar (ESP) 6-3, 6-2, 6-4
John Isner (USA x9) bt Casper Ruud (NOR) 6-3, 6-4, 7-6 (11/9)
Matteo Berrettini (ITA x17) bt Aljaz Bedene (SLO) 3-6, 6-3, 6-2, 7-6 (7/3)
Marcos Baghdatis (CYP) bt Brayden Schnur (CAN) 6-2, 6-4, 6-4
Dominik Koepfer (GER) bt Filip Krajinovic (SRB) 6-3, 4-6, 7-6 (11/9), 6-1
Diego Schwartzman (ARG x24) bt Matthew Ebden (AUS) 6-4, 3-6, 6-3, 6-2
Lucas Pouille (FRA x27) bt Richard Gasquet (FRA) 6-1, 6-4, 7-6 (7/4)
Grégoire Barrère (FRA) bt Alexander Bublik (KAZ) 3-6, 6-4, 6-3, 6-3
Jay Clarke (GBR) bt Noah Rubin (USA) 4-6, 7-5, 6-4, 6-4
Roger Federer (SUI x2) bt Lloyd Harris (RSA) 3-6, 6-1, 6-2, 6-2
Ashleigh Barty (AUS x1) bt Saisai Zheng (CHN) 6-4, 6-2
Alison Van Uytvanck (BEL) bt Svetlana Kuznetsova (RUS) 6-4, 4-6, 6-2
Harriet Dart (GBR) bt Christina McHale (USA) 4-6, 6-4, 6-4
Beatriz Haddad Maia (BRA) bt Garbiñe Muguruza (ESP x26) 6-4, 6-4
Ivana Jorovic (SRB) bt Lesley Kerkhove (NED) 7-6 (7/5), 6-4
Kaia Kanepi (EST) bt Stefanie Voegele (SUI) 5-7, 7-5, 6-4
Belinda Bencic (SUI x13) bt Anastasia Pavlyuchenkova (RUS) 6-2, 6-3
Serena Williams (USA x11) bt Giulia Gatto-Monticone (ITA) 6-2, 7-5
Kaja Juvan (SLO) bt Kristyna Pliskova (CZE) 6-4, 2-6, 6-4
Varvara Flink (RUS) bt Paula Badosa (ESP) 6-4, 6-2
Julia Goerges (GER x18) bt Gabriela Ruse (ROU) 7-5, 6-1
Carla Suárez Navarro (ESP x30) bt Samantha Stosur (AUS) 6-2, 7-5
Pauline Parmentier (FRA) bt Maria Sharapova (RUS) 4-6, 7-6 (7/4), 5-0 - retired
Lauren Davis (USA) bt Kateryna Kozlova (UKR) 6-3, 6-2
Angelique Kerber (GER x5) bt Tatjana Maria (GER) 6-4, 6-3
Kiki Bertens (NED x4) bt Mandy Minella (LUX) 6-3, 6-2
Taylor Townsend (USA) bt Arina Rodionova (AUS) 6-2, 6-3
Laura Siegemund (GER) bt Katie Swan (GBR) 6-2, 6-4
Barbora Zahlavova (CZE) bt Lesya Tsurenko (UKR x32) 6-3, 6-2
Elise Mertens (BEL x21) bt Fiona Ferro (FRA) 6-2, 6-0
Monica Niculescu (ROU) bt Andrea Petkovic (GER) 2-6, 6-2, 7-5
Tamara Zidansek (SLO) bt Eugénie Bouchard (CAN) 6-3, 5-7, 8-6
Wang Qiang (CHN x15) bt Vera Lapko (BLR) 6-2, 6-2
Sloane Stephens (USA x9) bt Timea Bacsinszky (SUI) 6-2, 6-4
Wang Yafan (CHN) bt Tereza Martincova (CZE) 6-2, 7-5
Katerina Siniaková (CZE) bt Ekaterina Alexandrova (RUS) 2-6, 6-1, 6-1
Johanna Konta (GBR x19) bt Ana Bogdan (ROU) 7-5, 6-2
Amanda Anisimova (USA x25) bt Sorana Cirstea (ROU) 6-3, 6-3
Magda Linette (POL) bt Anna Kalinskaya (RUS) 6-0, 7-6 (11/9)
Kristina Mladenovic (FRA) bt Vitalia Diatchenko (RUS) 7-5, 6-7 (4/7), 6-2
Petra Kvitova (CZE x6) bt Ons Jabeur (TUN) 6-4, 6-2