The 19-year-old tipped for the top will face the oldest remaining player when he plays 25-year-old American Brandon Nakashima in a Wednesday battle for a place in Thursday’s final.
Nakashima reached his breakthrough Masters semi in 77 minutes as he imposed his game on Luciano Darderi 6-2, 6-3, setting up three match points with his 11th ace as winning as the Italian missed on a drop shot.
Jodar shrugged off a slight tweak of his ankle in the second set against Fils and remained calm throughout as his French opponent smashed a racquet after being broken early in the second set.
Jodar, who does not turn 20 until after the US Open ends next month, has won 34 matches this season and played nearly every other day after reaching the final in Washington eight days ago.
Fils, back after injury, saved three match points in the final game before Jodar lanced a winner to the empty court after an hour and three-quarters in a match interrupted for an hour by rain.
“I played a very high level today against a tough player like Arthur,” Jodar said. “I had to give my best to win this match.”
After losing a break in the second set, Jodar earned a pair of insurance breaks on the way to victory.
“I knew I was doing things right, but he played a good game to break my serve. Things worked perfectly for me,” Jodar said.
“I stayed very calm during the pressure moments. I knew that even a set and a break up, the match was not finished. He always gives his best until the end.”
Nakashima, who won his fifth quarter-final of the season, credited his serve with keeping him on top against Darderi throughout the quarter-final, which was delayed a day after rain washed out the programme on Monday.
“My serve was super important. It got me out of some tough holes,” Nakashima said. “I had a lot of confidence going into the second set.
“I also took my opportunities on return when I needed to. I knew I had to open up the court. He was hitting his spots really well.”
Nakashima, into his 16th career semi-finals, put his confidence “at an all-time high.”
“I’m feeling great with every match. Hopefully we can keep this going,” he said. “It was a goal of mine at the beginning of the year to try to do well at one of these Masters 1000s tournaments. To be able to do it the for first time here is really special.”
The win was the seventh from eight matches for the Washington semi-finalist and marked his 26th victory this season. (AFP)