Second-seed WGM Soumya Swaminathan of PSPB suffered a shock defeat at the hands of WIM Michelle Catherina of Tamil Nadu on the top board in the fourth round of the Ram Ratna 42nd National Women's Challenger Chess Championship conducted by the Maharashtra Chess Association on Saturday.

Playing with white pieces, Soumya opted for 'd4' opening but on the 22nd move Catherina created an opening on the 'f' file. Top-seed IM Tania Sachdev of Air India was forced to play out a draw against Nandidhaa P in 22 moves.