Raced by Thai outfit Falcon Racing No 7 Stable, the O'Reilly four-year-old has now racked up four wins at his last five starts.
A winner at Class 4 level over seven furlongs at his last start one month ago, On Line was just as lethal when pitted against Class 3 rivals over a trip which connections had been looking to set him on for a while now – 1800m.
Ridden by champion apprentice jockey Simon Kok Wei Hoong, On Line enjoyed an economical run in transit. When the gaps opened up at the 300m, the bay gelding let down with a short sharp burst with only one horse between him and victory.
After drawing first blood upon straightening as race-leader Buddy Buddy (Ruan Maia) faltered, Japanese galloper Wind Trail (Marc Lerner) still showed plenty of cheek, but was eventually gathered in by On Line with 100m to go.
Three-quarter length separated them with Time Lord (Benny Woodworth) beaten in third place another two and a half lengths away. The winning time was 1min 48.6secs for the 1800m on the Long Course.
Clements saw the win as a confirmation that On Line can run a trip and can also account for better than bread-and-butter class.
"We've been wanting to run him over a distance for a while. He is bred for it, and everything he's done, he's shown that," said the Zimbabwean-born conditioner.
"It was a god confident ride from Simon. It was quite a soft win in the end as it was not the toughest of fields to beat.
"He's a progressive sort and I think he now has enough points to qualify for the 4YO series. We'll look at a Class 3 race over 1600m next and then run him in the second Leg – we wouldn't want to go for the first Leg."
The Singapore Four-Year-Old Challenge kicks off with the Group 3 Silver Bowl (1400m) in three weeks' time on February 29. On Line will be aimed at the second Leg instead, the Group 2 Stewards' Cup (1600m) on March 20.
The Group 1 Singapore Derby over 1800m is the third and last Leg and will be run on April 18, all part of a major departure from the later June-July time slot for the four-year-old challenge in the past.
Kok opined that such sterner tests would be well within the compass of the NZ$210,000 purchase as a two-year-old.
"He's a very smart four-year-old. It was a big step-up to go from 1400m to 1800m," said Kok.
"He was without blinkers today and he settled nicely for me. The track had a bit of rain, but he handled it well.
"He's got ability and he's very smart. In future, a step-up in distance will be much better for him."
With a handy record that now reads four wins and three seconds from eight starts, On Line has already gathered more than $170,000 in stakes earnings for the Falcon Racing No 7 Stable.