London - Serena Williams kicked off her bid for an eighth Wimbledon title with a hard-fought 7-5, 6-3 victory over Holland's Arantxa Rus on Monday.
The 23-time Grand Slam champion has now won her last 15 singles matches at Wimbledon after clinching the title in 2015 and 2016.
Williams, who missed Wimbledon last year to prepare for the birth of her first child, will play Bulgarian qualifier Viktoriya Tomova or Czech wild card Tereza Smitkova in the second round.
Wimbledon results on Monday, the first day of the 2018 championships (x denotes seeded player):
Men
1st round
Roger Federer (SUI x1) bt Dusan Lajovic (SRB) 6-1, 6-3, 6-4
Ivo Karlovic (CRO) bt Mikhail Youzhny (RUS) 4-6, 7-5, 7-6 (9/7), 6-3
Jan-Lennard Struff (GER) bt Leonardo Mayer (ARG x32) 3-6, 6-7 (5/7), 7-6 (7/5), 7-6 (7/5), 6-1
Adrian Mannarino (FRA x22) bt Christian Garin (CHI) 6-3, 1-6, 7-6 (7/4), 6-2
Ryan Harrison (USA) bt Roberto Carballes (ESP) 6-1, 6-4, 6-2
Guillermo Garcia-Lpez (ESP) bt Gasto Elias (POR) 6-2, 6-4, 6-2
Daniil Medvedev (RUS) bt Borna Coric (CRO x16) 7-6 (8/6), 6-2, 6-2
Sam Querrey (USA x11) bt Jordan Thompson (AUS) 6-2, 6-4, 6-3
Sergiy Stakhovsky (UKR) bt Joao Sousa (POR) 6-3, 6-3, 5-7, 1-6, 6-4
Gael Monfils (FRA) bt Richard Gasquet (FRA x23) 7-6 (8/6), 7-5, 6-4
Philipp Kohlschreiber (GER x25) bt Evgeny Donskoy (RUS) 6-2, 6-4, 7-5
Gilles Muller (LUX) bt Michael Mmoh (USA) 7-5, 4-6, 7-6 (9/7), 3-6, 6-1
Andreas Seppi (ITA) bt John-Patrick Smith (AUS) 6-2, 6-4, 6-1
Kevin Anderson (RSA x8) bt Norbert Gombos (SVK) 6-3, 6-4, 6-4
Marin Cilic (CRO x3) bt Yoshihito Nishioka (JPN) 6-1, 6-4, 6-4
Guido Pella (ARG) bt Jason Kubler (AUS) 6-4, 7-5, 4-6, 7-6 (7/3)
Mackenzie McDonald (USA) bt Ricardas Berankis (LTU) 4-6, 7-6 (8/6), 6-3, 7-6 (8/6)
Nicolas Jarry (CHI) bt Filip Krajinovic (SRB x28) 6-3, 3-6, 7-6 (7/5), 6-4
Lucas Pouille (FRA x17) bt Denis Kudla (USA) 6-3, 6-3, 2-6, 6-3
Dennis Novak (AUT) bt Peter Polansky (CAN) 6-2, 6-3, 7-6 (9/7)
John Millman (AUS) bt Stefano Travaglia (ITA) 6-7 (6/8), 6-3, 7-5, 6-2
Milos Raonic (CAN x13) bt Liam Broady (GBR) 7-5, 6-0, 6-1
John Isner (USA x9) bt Yannick Maden (GER) 6-2, 7-6 (7/4), 7-5
Stefanos Tsitsipas (GRE x31) bt Gregoire Barrere (FRA) 6-3, 6-4, 6-7 (3/7), 7-5
Jared Donaldson (USA) bt Malek Jaziri (TUN) 7-6 (7/5), 6-3, 6-1
Thomas Fabbiano (ITA) bt Yuki Bhambri (IND) 2-6, 6-3, 6-3, 6-2
Stan Wawrinka (SUI) bt Grigor Dimitrov (BUL x6) 1-6, 7-6 (7/3), 7-6 (7/5), 6-4
Women
1st round
Karolina Pliskova (CZE x7) bt Harriet Dart (GBR) 7-6 (7/2), 2-6, 6-1
Victoria Azarenka (BLR) bt Ekaterina Alexandrova (RUS) 7-6 (7/4), 6-3
Katie Swan (GBR) bt Irina Camelia Begu (ROM) 6-2, 6-2
Kiki Bertens (NED x20) bt Barbora Stefkova (CZE) 6-3, 6-2
Anna Blinkova (RUS) bt Wang Yafan (CHN) 6-7 (4/7), 6-4, 6-4
Alexandra Dulgheru (ROM) bt Kristyna Pliskova (CZE) 6-4, 1-6, 6-2
Venus Williams (USA x9) bt Johanna Larsson (SWE) 6-7 (3/7), 6-2, 6-1
Lesia Tsurenko (UKR) bt Timea Babos (HUN) 7-5, 6-2
Andrea Petkovic (GER) bt Zhang Shuai (CHN x31) 6-4, 4-6, 6-2
Yanina Wickmayer (BEL) bt Mona Barthel (GER) 7-5, 6-4
Rebecca Peterson (SWE) bt Viktoria Kuzmova (SVK) 7-6 (7/3), 7-6 (11/9)
Donna Vekic (CRO) bt Sloane Stephens (USA x4) 6-1, 6-3
Kristina Mladenovic (FRA) bt Anna Karolina Schmiedlova (SVK) 5-7, 6-2, 6-2
Serena Williams (USA x25) bt Arantxa Rus (NED) 7-5, 6-3
Sorana Cirstea (ROM) bt Magdalena Rybarikova (SVK x19) 7-5, 6-3
Evgeniya Rodina (RUS) bt Antonia Lottner (GER) 3-6, 7-5, 6-4
Luksika Kumkhum (THA) bt Bernarda Pera (USA) 4-6, 6-2, 6-3
Madison Keys (USA x10) bt Ajla Tomljanovic (AUS) 6-4, 6-2
Madison Brengle (USA) bt Aleksandra Krunic (SRB) 2-6, 6-3, 6-3
Camila Giorgi (ITA) bt Anastasija Sevastova (LAT x21) 6-1, 2-6, 6-4
Ekaterina Makarova (RUS) bt Petra Martic (CRO) 7-6 (7/0), 2-6, 6-3
Caroline Wozniacki (DEN x2) bt Varvara Lepchenko (USA) 6-0, 6-3