The Spaniard has been in dominant form so far this season, winning four of the seven ITU World Series events to date.
However, Jonathan Brownlee's triumph in Stockholm last weekend closed the gap between the two to 282 points, setting up a tense finale in Edmonton, Canada.
Gomez only needed to finish no worse than seventh to claim his fourth world crown, but failed to complete the course having suffered with illness in the build-up.
Jonathan Brownlee heads into the final event of the season knowing he needs to cross the line first to stand a chance of winning, while the title will belong to Gomez if he finishes fifth or better.
Alistair Brownlee has been hampered by injury this season, but followed brother Jonathan over the line for a Brownlee one-two in Sweden last weekend.
Olympic and Commonwealth champion Alistair will be keen to finish with a flourish and his involvement is likely to add an intriguing element to the battle between his sibling and Gomez.
Elsewhere in the field, Mario Mola, Joao Pereira and Richard Murray will not have given up hope of bringing the curtain down on the season with a win.
In the women's event, the United States' Gwen Jorgensen leads compatriot Sarah Groff by a hefty 848 points. A top-16 spot would be enough see her secure first place in the ranking list.
However, Jorgensen may be haunted by memories of last year's Grand Final, when a crash on the bike ended her chances for glory.
Reigning champion Non Stanford remains sidelined through injury, but fellow British athlete Jodie Stimpson is well-placed for a podium place and, while overall victory may seem unlikely, she could sneak into second - currently sitting 55 points adrift of Groff.
But Stimpson has not ruled out claiming top honours, and hopes the course can play to her strengths.
"It's going to be a fast swim again and I've just got to make sure I'm there on the bike where hopefully there's a small group and we can get something going," she is quoted as saying by 220 Triathlon. "This course is a cyclist's course, it's a hard course and there are some dedicated girls out there.
"If I'm in that first pack then I want to be joined by anyone who's up for working hard."