Alexander Zverev of Germany returns a backhand to Joao Sousa of Portugal during the BNP Paribas Open at the Indian Wells Tennis Garden in Indian Wells. Pic/AFP

World number five Alexander Zverev slumped to a shock 7-5, 5-7, 6-4 defeat to unheralded Joao Sousa in his opening match at the ATP Indian Wells Masters on Sunday night. Portugal's Sousa, who is ranked 85th in the world, advances to the third round where he will face Canadian No. 1 Milos Raonic who beat 17-year-old countryman Felix Auger-Aliassime 6-4, 6-4.