The fourth seed Ghosal produced a gritty performance as he rallied from two-game down to eke out a difficult 8-11 7-11 11-6 11-8 11-6 win over the 12th seed from New Zealand.
Ghosal thus became the first Indian to reach the singles semifinals since the sport was introduced in the Games programme in 1998.
However, it was heartbreak for Dipika, who went down to Alison Waters of England in the quarterfinals today.
Earlier, fourth seed Ghosal had a narrow escape against Australian Steven Finitsis as he recovered from 6-7 down in the fifth and deciding game to pull off a 11-2, 11-5, 4-11, 6-11, 11-8 victory.
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"I am really happy I won in the end. It was a really tough match. He (Finitsis) played really well from the third game. It was going neck and neck in the fifth but I managed to string together four points in a row to take the match," Ghosal told PTI after his gruelling 86-minute pre-quarterfinal.
After the match, the Commonwealth Games debutant said: "It was a tough match and I am happy to get through in straight games. My plan for the day was to play some solid squash and attack whenever I got an opportunity and I am glad that it worked it out well."
India has never won a squash medal at the Commonwealth Games since its inception at the quadrennial extravaganza.