The triumph made Andreescu, 18, the youngest Indian Wells champion since Serena Williams in 1999 and the first wildcard to take home the title from one of the biggest tennis tournaments outside of the four Grand Slams.
"I've never been in a situation like that before. Never been in a final of a premier event playing a very high-level opponent," Andreescu said on Tuesday during a conference call from Florida where she is competing in the Miami Open.
"So I think it was also all of the emotions and all of the tension that was going through my body that caused me to get even more tired than I usually would."
A struggling Andreescu called for her coach after falling behind 3-2 in the decisive third set of her win over three-times Grand Slam champion Kerber and said her "feet were burning" and that she was having trouble moving on the court.
Andreescu, who as a junior in 2016 missed six months due to stress fractures in her foot and last year missed action with back issues, said she has already taken steps to try to find ways to avoid further injuries.
"Tennis Canada has a great group of doctors and I've been running some tests with them to see what the problem is," said Andreescu. "But definitely after Miami I will take a good two or three weeks off just figuring out what to do better with my body and my nutrition and my mind."
Andreescu first made waves in January when she beat former world number ones Caroline Wozniacki and Venus Williams on consecutive nights in a tune-up event for the Australian Open where fatigue seemed to play a factor in her second round loss.
Still, the whirlwind start to the year, a period in which Andreescu has shot to 24th in the world rankings from 152nd, has given the Canadian a sense of confidence when competing against the world's best players.
"Now that I am gaining more and more experience and getting more and more confident playing against these top-level players I am definitely not starstruck anymore," said Andreescu, whose run in Indian Wells included wins over five seeded players.
"But I want to just go into every match not trying to focus on who's on the other side (of the net) and just focus on myself."
(Reporting by Frank Pingue in Toronto; Editing by Hugh Lawson)
