The 29-year-old netted the Hammers' second goal during their 3-1 win over West Bromwich Albion in the Premier League at the weekend.
O'Neil told West Ham TV: "It was similar to one I had up at their place this year that just missed the far post. I can't kick it as hard as some of the younger lads so I have to go for placement.
"It was nice to see one go in. It's about two years to the week since I got my injury in the game against Aston Villa here, so it's nice to get a Premier League goal.
"Obviously I got a couple in the Championship last year, but it's nice to get back on the scoresheet in the Premier League."
O'Neil has scored three goals for West Ham since joining the club in January 2011.