The course of events in the WTA 500 Cymbiotika San Diego Open does go more than well for the home crowd's favorites, as three of the players who reached out the phase of semifinals are the Americans.

Danielle Collins was considered as one of the favourites in this tournament, despite not being seeded in the draw. The "Danimal" showed signs of coming back to great form earlier on during the North American hard courts swing. Collins confirms the ambitious and abilities to clinch the title in California, as she displays an impressive tennis performance throughout whole the week. The match against Jelena Ostapenko in second round was one of the most spicy match-ups during whole the week and the battle has not disappoint at all. Collins was not feeling well from the start, as she lost the opening without taking up too much fight against the Latvian, who took it easily by 6-2. The player from Florida was not feeling well this day, as she called up the medical time-out twice, which was related to the pain felt in her lower back and hip. Despite the health issues, Collins showed a great fighting spirit, as she came back from being a break down in second set, and forced a decider by winning 4 games in a row.

This match was full of momentum switches, as Ostapenko dropped down the level after strong start, which in addition of great raise up of level from Collins, resulted with the eventual victory of the American, who has came back from being a break down also in deciding set, winning the whole thing by 2-6 6-3 6-4.

The task in quarterfinals was much easier for "Danimal", even despite she played against 2nd seed of the draw. Caroline Garcia won the match against Sloane Stephens to break through the series of miserable results scored in recent weeks, but her recent form was just not enough to be any dangerous for Collins, who showed an ultimate performance on Thursday. The current world's number 43 was a dominant force throughout both sets and moved into her second semifinals of the season after 6-2 6-3 victory. Collins was super consistent at this day, as she has not faced any single breakpoint during whole the match.

Barbora Krejcikova will be her opponent in semifinals. The Czech approached San Diego with the ongoing series of 4 loses in a row. Two weeks after disappointing first round exit in the US Open, Krejcikova looks seemingly better with her form, as she moved into semis after two confident straight set victories against Anhelina Kalinina and Beatriz Haddad Maia. The Brazilian fought hard for her place in quarters, advancing there after two tough three-setters, including the 3 hours fight against Marta Kostyuk. Maybe the lack of energy after demanding start of the week was one of the factors, that the Brazilian got dominated by Krejcikova in their Thursday's quarterfinals clash.

Sofia Kenin and Emma Navarro are surely the unexpected semifinal's pairing from the top half of main draw. The 2020 Australian Open champion advanced into her first semis since January, when she approached this stage in WTA 250 event in Hobart. Kenin performed two upsets against Russian players on the road, defeating Veronika Kudermetova and Anastasia Potapova in straight sets. Katie Volynets is the only one who gave away the single set for her, as Kenin needed to fight back from a set down against her fellowcountry in second round's match, but made it through with a final score 1-6 6-4 6-2.

Emma Navarro has needed to overcome the longest journey out of all the semifinalists, as she OKstarted her campaign in San Diego last weekend during the qualifying stage. After four consecutive straight sets wins, the biggest challenge appeared in the quarterfinals, as Navarro met 3rd seed Maria Sakkari. It was a thrilling battle, which started well for the home crowd's favorite, who won the opening set by 6-4. Sakkari responded more than well, as she forced the decider by winning second set with a bagel. Third set was a tight contention, where both the players traded two breaks, settling it all in the tiebreak. Navarro was on the front foot from the start of 13th game and held the nerves till the end, performing the best success in the career so far. It's her first ever semifinal of the tournament on WTA 500 level and first career's victory over the opponent ranked in top 10 of WTA rankings.