Coming off their win over the Seahawks the 49ers played against the Chargers at Qualcomm Stadium on Thursday Night. The 49ers fell behind 2 minutes into the game with QB Philip Rivers throwing a 58-yard TD pass to WR Vincent Jackson, followed in the second quarter by kicker Nate Kaeding nailing a 25-yard field goal, then with Rivers finding Jackson on an 11-yard touchdown pass. In the third quarter the 49ers had a touchdown from the second-half kickoff return but was declined because of a face-masking penalty enforced on them. Following that, they struggled further 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.

Based on the above article, answer a question. How many touchdown passes did Philip Rivers throw in the first half?
2