Courtois was left dizzy and bleeding from one ear after sustaining the blow in a collision with Arsenal winger Alexis Sanchez during Chelsea’s 2-0 win at Stamford Bridge last weekend.
The Belgium international was initially cleared to continue by Chelsea doctor Eva Carneiro, but was eventually replaced by Petr Cech more than 13 minutes later after his symptoms worsened.
Headway, a prominent charity that supports those suffering from brain injuries, questioned Chelsea’s handling of the situation and whether the Premier League’s new regulations, which dictate players must be substituted if a concussion is suspected, were adhered to.
But the 22-year-old, who played 90 minutes for Belgium in their 6-0 European qualifier win over Andorra on Friday, praised the work of his club’s medical staff.
“The doctor of Chelsea did well, I think,” Courtois on Sunday told Sky Sports. “She asked me the questions she needed to ask and I could repeat immediately so I was feeling well and didn’t have to come off.
“I didn’t feel I was knocked out but I was hit. I didn’t have a headache or anything, but after a few minutes I felt worse and worse.
“Then I started to feel a little dizzy and I couldn’t see the ball any more and there was a little blood coming from my ear. Because I saw trouble, I went off.
“I know you have to be careful, but I was not really knocked out.”
Courtois underwent a series of subsequent tests in hospital, which forced him to join up with Belgium a day later than the rest of the squad.
“I had some neck pains, dizziness, and headaches for a few days afterwards, so that’s why I stayed in England,” he added.
“I had neurological tests to see if my brain was responding correctly and, after it was okay, I travelled to Belgium.”