00:51 CET - A late night in Rotterdam on the court and it has been a good night for Holger Rune (21), who has beaten Lorenzo Sonego (29) 7-6(4), 6-4 to advance.
We still have plenty of tennis still to come overnight from Dallas, where Aleksander Vukic (28) takes on Australian Open semi-finalist Ben Shelton (22) from 02:00 CET.
That is followed by Marcos Giron (28) up against Casper Ruud (26) - follow that game here from around 03:30 CET.
We will be back bright and early to round up these matches and bring you all the results from another day on the tour.
00:10 CET - A brilliant comeback from Cameron Norrie (29) sees him through to the next round in Dallas after a 2-6, 7-6(1), 6-1 victory over Alex Michelsen (20).
22:16 CET - World number one Carlos Alcaraz (21) has won his first match since losing to Novak Djokovic in the Australian Open quarter-final but he was made to work against wildcard Botic van de Zandschulp (29).
The Spaniard won out in more than two-and-a-half hours 7-6(3), 3-6, 6-1 to go through to the next stage in Rotterdam.
21:53 CET - Back to Dallas, where third seed Tommy Paul (27) has seen off American compatriot wildcard Jenson Brooksby (24) in three sets 6-7(6), 6-3, 6-4 to progress.
21:05 CET - In an all-Spanish affair in Rotterdam, Pedro Martinez (27) has beaten veteran Roberto Bautista-Agut (36) 6-3, 6-2 to advance into the next round.
20:35 CET - Third seed Peyton Stearns (23) has overcome Varvara Gracheva (24) 2-6, 6-2, 6-2 to round off the day's play in Cluj, but that is not the biggest news from Romania this evening. Shortly after her earlier defeat, Simona Halep (33) announced her retirement from tennis.
The former Grand Slam champion gave a speech on court, which you can watch below.
Read more about the announcement now.
20:03 CET - Over in Cluj, wildcard Simona Halep (33), still making her way back into the sport following a doping ban, has been defeated 6-1, 6-1 to Lucia Bronzetti (26).
18:54 CET - A huge win for Ons Jabeur (30) in Abu Dhabi, with the Tunisian battling past seventh seed Jelena Ostapenko (27) in two hard-fought sets, 7-6(4), 7-5.
18:33 CET - Staying in Cluj, Anna Blinkova (26) and Ana Bogdan (32) are both through to the next round after comfortable wins over Sara Sorribes Tormo (28) and Jodie Burrage (25) respectively.
17:24 CET - Elisabetta Cocciaretto (24) has progressed in Cluj with a straight-set 6-3, 7-5 victory over home favourite Irina-Camelia Begu (34).
16:36 CET - It has been a really tough time for Marketa Vondrousova (25), who has been struggling with so many injury problems of late. However, the Czech looked in good touch in Abu Dhabi, beating Emma Raducanu (22) 6-3, 6-4 to claim just her second win since last July.
Andrey Rublev (27) claimed a straightforward win in Rotterdam too, easing past Zhizhen Zhang (28) 6-3, 6-4.
16:26 CET - Jakub Mensik (19) and Alexander Bublik (27) are just two spots apart in the ATP rankings, but it was not a close contest as Mensik saw off his Kazakh opponent 6-4, 6-4 in exactly one hour.
Meanwhile, in Abu Dhabi, sixth seed Anastasia Pavlyuchenkova (33) is through to the next round with a 6-3, 6-1 victory over Sofia Kenin (26).
14:54 CET - Third seed Alex de Minaur (25) is safely through in Rotterdam after seeing off experienced Belgian David Goffin (34) in straight sets, 6-2, 6-4.
Meanwhile, in Abu Dhabi, Belinda Bencic (27) continued her impressive return to the Tour with a 6-2, 3-6, 6-1 triumph over Rebecca Sramkova (28).
13:49 CET - Viktorija Golubic (32) has won an absolute thriller in Cluj-Napoca, overcoming Arantxa Rus (34) 7-5, 4-6, 7-6(10) in three hours and 32 minutes.
Magda Linette (32) also battled through in Abu Dhabi, beating qualifier Renata Zarazua (27) 6-4, 7-6(6).
13:25 CET - Olga Danilovic (24) has continued her good start to the season with a straight-set 6-3, 6-3 victory over Alycia Parks (24) in Cluj-Napoca.
12:45 CET - Jiri Lehecka (23) looked to be in really good touch in his opening round match in Rotterdam, swatting aside Alexei Popyrin (25) 7-5, 6-2.
12:25 CET - Leylah Fernandez (22) was involved in a real tussle in Abu Dhabi, eventually overcoming Moyuka Uchijima (23) 7-6(3), 7-6(0) in just over two hours.
11:33 CET - There is plenty of top action throughout the day to look forward to, with Carlos Alcaraz (21) and Alex De Minaur (25) set to take to the court a little later on in Rotterdam.
There are also some really exciting match-ups in Abu Dhabi this afternoon, with former Grand Slam champions Marketa Vondrousova (25) facing Emma Raducanu (22), and Ons Jabeur (30) taking on Jelena Ostapenko (27).
Follow the action in Rotterdam, Abu Dhabi, Cluj-Napoca and Dallas with Flashscore.
11:22 CET - The first few results of the day are in, with No. 1 seed Anastasia Potapova (23) easing past Julia Grabher (28) 6-4, 6-0 in Cluj-Napoca.
Over in Abu Dhabi, Linda Noskova (20) crushed Magdalena Frech (27) 6-0, 6-3.
09:07 CET - There were a couple of matches played overnight in Dallas, with fifth seed Frances Tiafoe (27) battling past Taro Daniel (32) 6-1, 3-6, 6-4 in a topsy-turvy affair and American qualifier Ethan Quinn (20) seeing off compatriot Trevor Svajda (18) 6-4, 6-2.
08:50 CET - Good morning and welcome to our coverage of today's tennis!