20:43 CET - In the final match of the day, Lorenzo Musetti (22) has battled to a 6-4, 4-6, 6-4 win over Brandon Nakashima (22) at Queen's.
That brings an end to today's action, but we'll be back tomorrow to continue our coverage as the four tournaments head towards their final stages. See you then!
19:50 CET - We have our second major upset of the day, with world number 11 Stefanos Tsitsipas (25) losing 6-4, 6-4 to Jan-Lennard Struff in Halle.
19:33 CET- Aryna Sabalenka (26) has cruised into the next round in Berlin with an impressive 6-1, 6-4 win against Daria Kasatkina (27).
19:25 CET - Despite being strong on grass, Matteo Berrettini (28) has been knocked out of Halle by American Marcos Giron (30). Giron won 6-3, 4-6, 6-3.
18:00 CET - In Berlin, fourth seed Jessica Pegula (30) has won 6-4, 7-5 against Donna Vekic (27) and eighth seed Ons Jabeur (29) has beaten Linda Noskova (19) 6-7, 6-3, 6-4.
16:11 CET - The top two men's seeds are both on the grass-courts and with very differing results. Number one Jannik Sinner (22) has made hard work of beating Fabian Marozsan (24) in three sets, 6-4, 6-7(4), 6-3 to advance into the quarters.
But, we have a shock at Queen's where home favourite Jack Draper (22) has produced a superb display to beat Carlos Alcaraz (21) 7-6(3), 6-3 for the biggest win of his career.
15:43 CET - Back to Birmingham, where Diana Shnaider (20) has seen off Marie Bouzkova (25) in straight sets 7-6(5), 6-3 to advance into tomorrow's quarter-finals.
15:40 CET - Top seed Coco Gauff (20) survived a tense opening set to get the better of Ekaterina Alexandrova (29) in Berlin. The American triumphed 7-6(6), 6-2.
13:43 CET - Hubert Hurkacz (27) is safely through in Halle, battling past James Duckworth (32) 7-6(3), 6-4 in two close sets. Meanwhile, in Birmingham, Yulia Putintseva (29) has booked her place in the quarter-finals after an emphatic 6-3, 6-0 victory over Anhelina Kalinina (27).
12:50 CET - World number four Elena Rybakina (25) has beaten Veronika Kudermetova (27) 6-4, 7-5 in Berlin, while world number six Marketa Vondrousova (24) has retired with an injury against Anna Kalinskaya (25).
10:05 CET - Carlos Alcaraz (21) and Jannik Sinner (22) continue their preparations for Wimbledon today, while Alexander Zverev (27), Stefanos Tsitsipas (25) and Hubert Hurkacz (27) also take to the court.
Meanwhile, on the women's tour, former Wimbledon champion Elena Rybakina (25), Aryna Sabalenka (26) and Coco Gauff (20) all begin their campaigns in Berlin.
Check out the schedules for all four of this week's tournaments below:
09:30 CET - Good morning and welcome to our coverage of today's tennis!