It was not long before Raducanu raced into a 5-0 lead in the second set, looking destined to seal an easy victory. But she put her position under question when she missed the chance to bagel with two double faults on match point, allowing Uchijima to break back for the first time.
That opened the door for Uchijima, who suddenly looked reborn and fought back with four successive games to crank up the heat on Raducanu, whose self-doubt was evident after challenging for a line call before changing her mind.
She dug out two aces when facing a break point after serving up a double point. And 20 minutes after her first match point, she took advantage of her third with a strong serve down the middle.
Her coach Dmitry Tursurnov, watching on from the stands, would have been slightly concerned with how she finished the match but pleased with her overall display as she took home a morale-boosting win.
She will face Yanina Wickmayer in the second round of the tournament after the Belgian overcame 17-year-old sensation Linda Fruhvirtova in straight sets.
