Moloney, 21, finished day one in commanding style on Wednesday with the leading performances in the high jump (2.11m) and his pet event, the 400 metres (46.29sec).

The 2018 world junior champion had 4641 points after five of 10 events, just behind the early pacesetter, Canadian Damian Warner (4722), who began the competition with a blistering 100 metres run of 10.12.

Another Canadian Pierce LePage was third overall with 4529.

"It's been a bloody long day. My first Olympics and the schedule's way out of my comfort zone," said Moloney.

"I'm used to bang, bang, bang, next event, next event.

"Having a break during the day means you can turn off, have a half day almost.

"It's been a awesome day. I'm in a decent position but I'm really going to pick up on day two to keep that place."

Australian Cedric Dubler is in 15th spot on 4184, having battled a hamstring injury in the lead-up to the Games.

The concluding five events take place on Thursday.

Australian Associated Press