Giovani Hernandez netted a controversial injury-time penalty, cancelling out Nathan Dyer's second-half opener, as honours were shared in a tense battle at Miller Park in Milwaukee.
Both teams were forced to play the remaining 10 minutes with 10 men after Neil Taylor and Jesus Sanchez saw red for a heated exchange.
Swansea manager Gary Monk named Angel Rangel captain for the Premier League club's first pre-season fixture in the absence of Ashley Williams, who flew home to Wales due to family reasons.
New signings Lukasz Fabianski, Bafetimbi Gomis and Stephen Kingsley were all handed starting berths.
And high-profile recruit Gomis, who arrived from Ligue 1 side Lyon, made an impressive start to proceedings but the French striker was unable to find the net from close range in the sixth minute.
Former Arsenal goalkeeper Fabianski was called into actions moments later to deny Guadalajara's Angel Reyna, while Wayne Routledge had a goal ruled out for offside soon after.
Monk made 10 changes at the interval, introducing the likes of Dyer, Leon Britton and new recruit Marvin Emnes.
Second-half substitute Dyer made an immediate impact, breaking the deadlock in the 57th minute, after some good build-up play between Taylor and Emnes.
Tensions threatened to boil over late on when Taylor and Sanchez clashed off the ball, resulting in both players being dismissed.
And just as Swansea seemed destined for victory, Guadalajara were awarded a penalty in the closing stages and Hernandez converted the spot-kick past substitute keeper Gerhard Tremmel.
