WATCH: Chidiac scores her first goal for Louisville; Wave stay on top
Alex Chidiac found the back of the net for the first time for Racing Louisville; while Wave FC hung on to first.
Kansas City came from behind to extend their unbeaten run to eight games, while San Diego defeated last season's NWSL runners-up in a thrilling 1-0 win.
Kicking off in Louisville, Portland Thorns opened the scoring in the 7th minute of the game through Sophia Smith, placing her left-footed shot into the side netting. At the 30th minute mark, it was Alex Chidiac that would fashion the equaliser, netting her first NWSL goal and first for Racing.
Chidiac picked up the ball near the corner flag and danced along the end line, squeezing her goal past a sea of defenders from an almost impossible angle to restore parity going into the break.
Hina Sugita had the match-winner for Thorns in the 74th minute, burying a rebounded shot to extend Portland's unbeaten streak to nine games.
Despite the loss, Alex Chidiac was named Player of the Match.
Moving over to Chicago, Emily van Egmond's Wave FC were looking to get back to winning ways and hang on to the top of the table when they took on the Chicago Red Stars.
Van Egmond made her 14th start of the season, and it was the visitors that would have the opener, 17-year-old Jaedyn Shaw, making her Wave FC debut, netted the match winner in the 27th minute.
Chicago had the chance to net an equaliser in the 82nd minute, awarded a penalty kick after Ella Stevens was bought down in the box by Naomi Grima. However, for the second game in a row, Wave FC denied the opposition from the spot, this time Kalian Sheridan making the save on Mallory Pugh's effort.
This win sees Wave FC go one point clear of Portland Thorns at the top of the ladder.
Finishing off in Kansas, Chloe Logarzo's Kansas City Current came from behind to extend their unbeaten run to eight games with a 2-2 draw with the Orlando Pride.
Celia Jiménez gave Pride the lead going into the break, with the defender heading the ball past Adrianna Franch in Current's goal. Julie Doyle added Orlando's second just 23 seconds into the second half, however, Elyse Bennett and Cece Kizer both found the back of the net late in the game for Kansas to salvage a point.