"I had a little bit of a sore finger for the last couple of weeks which I don't think was a big factor, but confidence wise I didn't get in the right position. The shot put is not a big scorer so I was only down about 20 points," he said.
He cleared 1.96m in the high jump, narrowly missing on his last attempt to equal his personal best at 1.99m.
"I knew I was ready for a big high jump and once again I was just a bit unlucky with getting an equal PB, but it was a season's best and my best jump in a while."
The 26-year-old finished the first day clocking 49.95s over 400m for a total of 4046 and 18th place.
"The 400m in 49.95s is not the end of the world. I was hoping for a little bit more but we're just off the pace for an overall PB," said Newdick.
The second day of the decathlon started with the 110m hurdles and Newdick finished seventh in his heat in 14.86s, in the discus he threw 45.65m, just under two metres short of his best.
In the pole vault, where his best is 4.80m, he cleared 4.30m and 4.50m at his first attempt, passed at 4.60m and missed three attempts at 4.70m.