"contest commenced" is correct and usable in written English.
You can use it to refer to the beginning of a competition. For example, "The contest commenced at noon today and will end at midnight tomorrow".
The soccer-playing nations of the continent have come together, and the knockout stages of the contest commence on Saturday.
A Texas Confederate officer wrote to his wife in 1864: "I am sick of war" and of "the separation from the dearest objects of life," his wife and children, but "were the contest again just commenced I would willingly undergo it again for the sake of … our country's independence and [our children's] liberty".
Levesque began competing in bodybuilding contests in 1987, and commenced his professional wrestling career in the International Wrestling Federation in 1992, under the ring name Terra Ryzing.
Nominations can be made from June 1, the contest proper will commence on July 8 and the winner will be announced on September 2. Candidates to be put on the assembly member "party list", elected by a complex form of proportional representation, will emerge from the same timetable.
Kick-off commenced less than 15 minutes after the conclusion of the contest in Newcastle, on an otherwise full round of matches.
Lines of voters snaked down streets outside polling places in Lusaka, the capital, an hour before voting commenced on Thursday, one indication of the country's absorption with the contest.
Having returned yesterday evening from melancholy business overseas, I commenced my re-engagement with the capital's democratic process by watching a live quarreling contest on the BBC.
Following an international contest for the city's design, a blueprint by the Chicago architects Walter Burley Griffin and Marion Mahony Griffin was selected and construction commenced in 1913.
