The phrase "a substantial margin in" is correct and usable in written English.
It can be used when discussing a significant difference or advantage in a particular context, such as performance, scores, or results.
Example: "The team won the match with a substantial margin in points, securing their place in the finals."
Alternatives: "a significant lead in" or "a considerable advantage in".
High-school children in Shanghai outscored those elsewhere by a substantial margin in reading, the report's focus.
The Security Council, where China has a veto, would never have accepted this, and Taiwan's voters rejected the idea by a substantial margin in last week's election.
"We're going to have a six- or seven-point victory and a substantial margin in the Electoral College of 320 votes or so," Mr. Rove said.
Pro-Canada forces won by a substantial margin in 1980 and by only a whisker - roughly 50,000 votes - in 1995.
He trimmed three-twentieths of a second — a substantial margin in this race — off Johnson's time from the lonely outpost of the eighth lane.
Karl Rove, Mr. Bush's chief strategist, had told The New York Times two days before the election, "We're going to have a six- or seven-point victory and a substantial margin in the Electoral College of 320 votes or so".
The bold maneuver would probably be used only if the team were trailing by a substantial margin and in desperate need of a spark.
Her associates say that she and her advisers are well aware that capturing a substantial portion of the upstate vote could help her achieve a substantial margin of victory in November that could, in turn, give her momentum in advance of a potential presidential bid.
For both rice and sorghum pairs, rearrangement is most common in maize (Figs 1B and 2B) by a substantial margin and is least common in Brachypodium (Figs 1C and 2C).
While he couldn't make a silk purse from a sow's ear the last five or six years when emerging markets were doing poorly, he has beaten his benchmark from inception by a substantial margin, doing an exceptional job in relative terms.
The PPP poll showed Obama leading Mitt Romney in Massachusetts by 14 points, a substantial margin, but the slimmest lead they've recorded for him in the state.
