Raducanu struggled in the first set before finding her stride in the second, but couldn’t hang on for victory.
There were three breaks of serve in the first three games, before Raducanu eventually held her serve in the fourth.
She started to assert herself but could not take advantage of four set points, allowing Friedsam to level the opening set and take the lead.
Raducanu began to move awkwardly after grabbing her left leg, and Friedsam eventually took the opening set when the 19-year-old put a forehand wide.
Raducanu took a medical timeout between sets and showed grit when she returned, instantly breaking Friedsam, despite strapping on her thigh, and quickly going 4-0 up.
The British No. 1 stormed through the remainder of the second set, taking advantage of Friedsam’s dip in energy to win the set 6-0.
However, Raducanu, the tournament’s top seed, could not find an answer in the third as Friedsam found her stride once again, frequently pushing Raducanu back behind the baseline.
Late in the third, Raducanu produced an untimely error — double faulting — to give Friedsam her first break point in the final set.
The German took advantage of the opportunity, hitting a strong return and breaking to go up 5-3 and serve for the match.
The 28-year-old made light work of the final game to close the set out and move onto the quarterfinals, while Raducanu continues to look to return to the form she showed en route to winning the 2021 US Open.