Rodriguez, 26, had not played in a competitive fixture for 16 months after he ruptured his anterior cruciate ligament in a Premier League fixture against Manchester City in April 2014.
The England international featured regularly throughout pre-season though, and managed 65 minutes in the 2-2 draw at St James' Park before being replaced by Shane Long - who scored a 79th-minute equaliser.
Koeman, who was standing in for brother and manager Ronald after he underwent Achilles surgery last week, was delighted to see Rodriguez back in action.
"I think for him it was a big victory to start. He trained already for six weeks with us and he makes some minutes so he was ready for it," Koeman said.
"After that long period, maybe 15 or 16 months without a game, I have to say he did very well."
