Raonic was beaten 4-6, 7-6 (4), 6-7 (6), 7-5, 6-4 by 10th-seeded Nishikori on Monday in a four hour 19 minute struggle that tied a record as the latest-to-finish match in U.S. Open history.
"You learn from losses like that, you rebound and that's what makes a champion," said Martin Laurendeau, the captain of Canada's Davis Cup team.
"It was the kind of match I was expecting. Four or five sets very close. I didn't expect it to finish that late but we knew it would be a long night in New York. In a way that's a bit of what makes New York New York. . . The crowd stays up late."
On Tuesday, Laurendeau named Raonic, Frank Dancevic, Daniel Nestor and Vasek Pospisil to the team that will battle Colombia beginning Sept. 12 in Halifax.
One thing the players won't have to deal with in Halifax will be the sweltering heat at the U.S. Open. Canada's Eugenie Bouchard needed a medical time-out as she was eliminated by left-hander Ekaterina Makarova earlier Monday.
"The conditions will be significantly different in Halifax," said Laurendeau. "We'll be playing indoors under some nice air conditioning, which is going to welcomed."
Raonic went 5-1 in Davis Cup action last year to help lead Canada to the semifinals and at No. 6 is the highest-ranked Canadian singles player of all time.
Canada started the season in the World Group for the third consecutive year, playing their first-round tie on the road in February against Japan in Tokyo.
But injuries to Raonic and Pospisil contributed to a disappointing 4-1 loss, forcing this match against Colombia to stay in the World Group. Canada enters as the favourite, ranked eighth in the world to Colombia's 26th. The Colombian Tennis Federation is sending Santiago Giraldo, Alejandro Falla and doubles pair Juan Sebastian Cabal and Robert Farah.
"Our guys are healthy," Laurendeau said. "They've played a lot of tennis. They've accomplished a lot of personal milestones in the process."
Dancevic, who took Canada's sole point in Japan in February with a victory over Go Soeda, won a Challenger event in Kosice and reached the second round at Wimbledon.
This is Nestor's 22nd year playing Davis Cup and he's on a roll after capturing four ATP World Tour titles at Brisbane, Sydney, Madrid and Rome and he's currently ranked No. 5 in the world.
Pospisil also started 2014 on a roll, reaching the semifinals at Chennai, the third round at the Australian Open and a career-high ranking of No. 25 before being sidelined with a back injury. This summer he started a doubles partnership with American Jack Sock that saw the duo go on a 14-0 run, including the Wimbledon championship.
This year Raonic became the first Canadian man in the Open Era to reach the quarter-finals of a Grand Slam at the French Open and then made the semifinals at Wimbledon. He is the only player on the ATP World Tour to have made the quarter-finals or better at six Masters 1000 events this year.
Laurendeau says they're feeling confident.
"And also very motivated to stay in the World Group and have another go at it next year, because we feel we had a good run last year but we feel we can go even deeper."
As for Raonic, Laurendeau says he has time to rest before Halifax.
"He's our No. 1 player. He's got a job to do soon."