04:40 CET - Christopher Eubanks is onto round 2 in Houston as he knocks off Rinky Hijikata 6-2, 4-6, 6-3. The American served no double faults in this one as he held on in the third to progress.
02:45 CET - Amanda Anisimova is moving on in Charleston. The 23-year-old topped Veronika Kudermetova 6-2, 6-2. Despite facing five break points, the world number 16 was seldom broken throughout the contest as she advances in just over an hour.
02:20 CET - Ethan Quinn pulls off the upset as he stuns Jordan Thompson 4-6, 6-4, 6-3. The American wildcard broke his opponent's serve five times throughout the contest as he progresses to the second round in Houston.
01:15 CET - Danielle Collins takes out Robin Montgomery 6-3, 6-1 to move on in Charleston. The number seven seed never faced break point as she served very well throughout the match.
00:35 CET - Shuai Zhang has prevailed in Charleson, knocking off Lucia Bronzetti 7-5, 5-7, 6-4. The qualifier led 4-0 in the deciding set. But, despite the Italian making it 4-4, Zhang broke her once more before closing out the match.
23:56 CET - The Bogota number one seed Marie Bouzkova has come through a scare to beat Aleksandra Krunic 6-0, 3-6, 6-2.
And just moments ago in Bogota, teenage sensation Iva Jovic stunned third seed Alycia Parks to claim an impressive straight sets win, 6-1, 6-4.
23:40 CET - Meanwhile, world number four Madison Keys has safely secured her place in the next round in Charleston with a dominant 6-3, 7-6 (7-4) win over Caroline Dolehide.
23:33 CET - Laura Pigossi has stunned Laura Siegemund in three sets to claim a huge 4-6, 6-1, 6-1 scalp in Bogota.
21:27 CET - Back to Charleston and home player Ann Li has booked her place in the next round with a comfortable 6-4, 6-3 win over Anna Blinkova.
And just moments ago, another American booked their place into the second round at Charleston as Hailey Baptiste defeated world number 100 Olivia Gadecki.
21:21 CET - Meanwhile in Houston, veteran Adrian Mannarino has got the better of Yannick Hanfmann to secure a 7-6 (7-5), 6-3 win.
20:55 CET - The final match of the day in Marrakech has come to a close as Hugo Gaston avoided an upset to beat Argentine player Juan Cerundolo 5-7, 6-3, 6-4 in an impressive comeback win.
20:40 CET - Over to Charleston, and one of the higher-ranked players in action today Sofia Kenin has made no mistake in putting away fellow American Bernarda Pera, as she won 6-3, 6-4.
20:17 CET - As play in Marrakech nears the end for the day, Pierre-Hugues Herbert has come through three sets to beat Federico Coria 4-6, 6-3, 6-2.
20:00 CET - It's a serene path into the last 16 for second seed Camila Osorio in her home tournament of Bogota - she has beaten wildcard Mariana Isabel Higuita Barraza 6-0, 6-1 to progress.
19:35 CET - The best of the day's play was saved until last in Bucharest as veteran Stan Wawrinka is through to the next round after a 194-minute battle against qualifier Timofey Skatov.
The Swiss 40-year-old, a wildcard this week, won the final set tie-break 7-1 to win the tie 6-4, 6-7(5), 7-6(1).
19:29 CET - Plenty of action in Bogota today, and we already have a couple of results with seventh seed Sara Sorribes Tormo out in the round of 32, beaten by France's Selena Janicjevic 6-1, 6-2 in 88 minutes.
18:08 CET - Mattia Bellucci has progressed in Marrakech, defeating Pavel Kotov in two hard-fought sets, 6-4, 6-4, while experienced Spaniard Pablo Carreno-Busta in also through after a straight-set triumph over Younes Lalami Laaroussi.
16:32 CET - Gabriel Diallo is through in Bucharest after a 7-6(5), 7-6(2) win over Taiwan's Chun Hsin Tseng.
Meanwhile, in Marrakech, we have had a shock as Polish qualifier Kamil Majchrzak has knocked out sixth seed Jaume Munar 6-4, 6-3.
16:00 CET - Finland's Otta Virtanen is through in Marrakech, battling past Daniel Altmaier in three sets, 6-2, 4-6, 7-6(3).
Meanwhile, in Bucharest, fifth seed Roberto Bautista-Agut recovered from a set down to outlast Yunchaokete Bu 3-6, 6-2, 6-2.
14:56 CET - Over in Marrakech, Jesper De Jong is safely into the next round after coming through a tight opening set to defeat Elliot Benchetrit 7-5, 6-1.
13:58 CET - Eighth seed Camilo Ugo Carabelli has produced an assured display, seeing off the challenge of Radu Albot 6-4, 6-3 to progress in Romania.
13:55 CET - Defending champion Marton Fucsovics is the latest man through in Bucharest, with the Hungarian sweeping aside Luca Nardi in straight sets, 6-3, 6-1.
12:54 CET - Somewhat of an upset in Bucharest as world number 232 Filip Misolic is through to the last 16 after seeing off Kazakhstan's number two Alexander Shevchenko in straight sets 6-3, 6-4.
12:37 CET - Christopher O'Connell has sealed his spot in the next round in Bucharest after a fairly routine 6-4, 6-3 triumph over experienced Serb Dusan Lajovic.
Damir Dzumhur is also through in Romania, easing past Valentin Vacherot for the loss of just three games.
10:28 CET - The best of today's action comes in Charleston, where Australian Open champion Madison Keys begins her campaign against compatriot Caroline Dolehide at 21:30 CET.
Maria Sakkari, Danielle Collins and Amanda Anisimova also take to the court at the stacked WTA 500 event.
Elsewhere, Jordan Thompson, Stan Wawrinka and Marie Bouzkova are among the names involved in other clay-court tournaments around the world.
Check out the full schedule for tournaments in Charleston, Houston, Marrakech, Bucharest and Bogota via the links.
09:45 CET - Good morning and welcome to our coverage of today's tennis!