The world No 23 did race into a 4-1 lead but the wily Hercog soon found her rhythym and disrupted Raducanu’s tempo, winning five consecutive games to take the first set 6-4 in 46 minutes.
The Bromley local battled back and after failing to take three break points at 1-2 in the second set, then saved two break points on her own serve, the second at 5-5 with a clever short backhand slice.
And it arguably proved to be a decisive moment in the match as the British number one roared with delight after converting her third set point to take it 7-5 when Hercog sent a forehand long.
After showing incredible mental strength, the momentum was firmly with Raducanu and she stormed through the final set to complete a memorable win.
