He grabbed the clubhouse lead at the SMBC Singapore Open before the US$1 million was suspended due to lightning threats on Thursday.
The eight-time Sunshine Tour winner mixed seven birdies and two bogeys to open up a one shot lead on Spieth and Korea’s Byeonghun An at the Serapong Course, Sentosa Golf Club.
“I’m really happy with my result today as I haven’t played here for a couple of years,” said the 44-year-old Horne.
“Whenever I do come over here, I generally play well, so it’s nice to renew my friendship with the golf course. I had a bit of a walkabout in the middle of the round but then I also had a good run coming in.
“I think they (Spieth and An) were just born when I turned professional, so it’s always nice when you play well and get off to a great start.
“I putted great today which was important. I put a new driver in the bag today and I hit it so far and straight and that made a huge difference.”
Spieth, who played the layout for the first time, was happy with his flawless performance and credited his putting for the share of second.
“My speed control was great, with no three putts,” the American Major winner said.
“I had a lot of putts over 30 feet today, I know I was not hitting it close enough but I managed to hit the fairway to a good number and get onto the greens where I just need to two-putt. It was pretty stress free and but there were no real opportunities.”
Compatriot Jbe’ Kruger opened with a 71, while Horne’s fellow Lumenrock International Sport management stable-mate Shaun Norris – who broke through for his maiden Asian Tour win in the 2015 Yeangder Tournament Players Championship – was one under par through 17 holes when play was suspended.
Norris and 56 other players will resume their first round rounds at 7.30am with the second round scheduled to commence at 8.10am.