Ross County manager Malky Mackay was left frustrated as his side slumped to an opening-day defeat to Celtic.
The Staggies could not take advantage of some early chances against the champions, which mostly fell for Simon Murray.
Mackay said: “I thought we started well and international teams will score goals against Celtic. They just have, Yokohama, Athletic (Bilbao). We get those chances in the first 15 minutes and should have scored. If it’s an international team, Celtic are 2-0 down.
“Our shape and system were good, our discipline were good, and we give away a stupid penalty. Then we don’t defend a cross in the last minute of the first half and next minute we are 3-0 down at half-time.”
County hit back through Jordan White before James Brown scored in stoppage-time via Starfelt’s deflection after O’Riley had netted Celtic’s fourth.
Mackay added: “I know at 3-0 here that can go on to become six or seven. My challenge for them at half-time was to be brave and go and score a goal and press high.
“Sometimes we were able to do it and sometimes we didn’t because we have some new players who aren’t quite there with the explanations I give them but I was really happy with how brave they were in the second half.”
