The Chargers' fourteenth game was an interconference duel with the 49ers which was played on Thursday Night. The Chargers took a quick lead with QB Philip Rivers throwing a 58-yard TD pass to WR Vincent Jackson. The lead was extended in the second quarter by kicker Nate Kaeding nailing a 25-yard field goal, followed by Rivers finding Jackson on an 11-yard touchdown pass. The Chargers continued to dominate with FB Mike Tolbert getting a 1-yard TD run, followed by Rivers connecting to Jackson on a 48-yard TD pass, then with Kaeding hitting a 39-yard field goal. The 49ers made their only score of the game with RB Brian Westbrook getting a 1-yard TD run. This game was also a blowout and San Diego improved to 8-6.

Based on the above article, answer a question. How many touchdown passes did Philip Rivers throw in the first quarter?
1