Myneni, who is ranked 451, overcame the 202-ranked Belgian 1-6 6-3 7-6(4) in a close to two-hour second round contest of the USD 50,000 Challenger tournament.
The big-serving Myneni next faces his Asian Games silver medal winning partner Sanam Singh.
Sanam entered the quarterfinals with a hard-fought 4-6 7-6(5) 6-3 win over compatriot and qualifier N Vijay Sundar Prashant after battling for two hours and 14 minutes in his second round.
Top seed from Kazakhstan Aleksandr Nedovysov also advanced with a 6-3 6-4 win over Belgium's Germain Gigounon.
Meanwhile, the Somdev Devvarman combined with left-hander Jeevan Nedunchezhiyan to upset Thai top seeds Sanchai and Sonchat Ratiwatana 4-6 6-4 10-7 in the first round of the doubles event.
