The top-seeded Swede, who lost his opening clay match in Barcelona last week, is preparing for next month's French Open. He has reached two finals at the clay-court Grand Slam tournament.
Soderling faces a stern test in the quarterfinals against eighth-seeded Juan Martin del Potro, who beat him in straight sets in Miami. The Argentine advanced after overcoming Alejandro Falla 6-2, 6-1.
Soderling overpowered Chardy in the first set, winning four straight games after twice breaking the Frenchman and twice not conceding a point on his own serve.
Both players were plagued by unforced errors in the second set and broke each other three times apiece.
A dispute with the umpire over a call in the second game of the third set appeared to unsettle Chardy, allowing Soderling to rack up 13 straight points.
The fifth-ranked Soderling, the only top 10 player in Portugal, had a bye into the second round.
The Swede made a strong start to the year, clinching titles in Marseille, Rotterdam and Brisbane before going out in the third round of Masters events in Indian Wells and Miami last month.