The phrase "a formidable challenger in" is correct and usable in written English.
It can be used to describe someone or something that poses a significant challenge or competition in a particular field or context.
Example: "The new startup has emerged as a formidable challenger in the tech industry, disrupting established companies with its innovative solutions."
Alternatives: "a strong competitor in" or "a significant rival in".
In Auckland, Coe's British teammate, Peter Elliot, will also be a formidable challenger in the 1,500.
For starters, Mr. Spano had a formidable challenger in Ms. Stewart-Cousins, a personable and spirited five-term county legislator from Yonkers.
Coke faces a formidable challenger in Pepsi.
On Thursday, he reiterated his belief that she will be a formidable challenger if she decides to run for the presidency in 2008.
The always brash Rick Dutrow Jr., however, believes he has a formidable challenger to Uncle Mo in his own barn -- Boys at Tosconova.
So, too are the attention, money and presence of a formidable challenger, Abigail Spanberger, in the contest.
Mr Obama is now standing in one of the most dangerous places on earth the road between Mrs Clinton and the White House.Mr Obama also has a formidable challenger on his left in John Edwards.
In the comedy series race, "Modern Family" -- which has dominated during its four-year Emmy run -- will probably face off against a new, formidable challenger in Netflix's "Orange Is the New Black".
— His status as a formidable challenger to Mitt Romney diminished in recent days, Rick Santorum took the stage at a gathering of religious conservatives on Saturday morning and implored them not to sell their convictions short.
But she is up against a formidable challenger, Marina Silva, a former rubber tapper in the Amazon and now the Socialist Party candidate.
That's a strategy that has worked well for companies such as Harley Davidson, and the new line of cruisers from Indian are proving a formidable challenger to the hold Davidson has enjoyed in Indian's absence from the consumer marketplace.
