Dominika Cibulkova wins in Acapulco
The top-seeded Slovak, runner-up in the Australian Open in January, won her fourth career title and first since Stanford in 2013.
"It was a tough match, I'm really tired, I had to dig deep physically and mentally," Cibulkova said. "She was very aggressive and kept coming back, but it's a final and thanks to my experience I was able to do it."
The 21-year-old McHale, ranked 70th, reached her first tour title match. Previously, her best results were two semifinals in Quebec, in 2010 and 2011.
"I'm a little bit sad because I didn't win, but at the same time I know that Dominika is a very good player and I fought until the end," McHale said.
"I learned that I have the capacity to go far in tournaments, that I'm capable of playing against the best, so I'm going to keep working every day to get better."
McHale is one of six Americans aged under 25 who are between 18 and 70 in the WTA rankings, along with Lauren Davis (64), Alison Riske (46), Madison Keys (38), Jamie Hampton (31) and Sloane Stephens (18), and they represent the next generation of U.S. talent as the Williams sisters come toward the end of their careers.
"There are several Americans going up in the rankings, we are pushing each other to be better," McHale said.