Coming off their season-sweep of the Chiefs, the Chargers flew to Raymond James Stadium for a Week 16 interconference duel with the Tampa Bay Buccaneers.  In the first quarter, San Diego struck first as quarterback Philip Rivers completed an 11-yard touchdown pass to tight end Brandon Manumaleuna.  The Buccaneers would respond with fullback B.J. Askew getting a 1-yard touchdown run.  The Chargers would answer in the second quarter Rivers completing a 15-yard touchdown pass to tight end Antonio Gates, followed by kicker Nate Kaeding getting a 28-yard field goal.  Tampa Bay would answer with kicker Matt Bryant getting a 49-yard field goal.  San Diego would close out the first half with Kaeding's 57-yard field goal. The Buccaneers would take the lead in the third quarter with quarterback Jeff Garcia getting a 7-yard touchdown run and completing a 71-yard touchdown pass to wide receiver Antonio Bryant.  Afterwards, in the fourth quarter, the Chargers rallied to victory with Rivers completing a 5-yard touchdown pass to Gates and a 32-yard touchdown pass to running back Darren Sproles, followed by cornerback Antoine Cason returning an interception 59 yards for a touchdown. With the win, San Diego kept their playoff hopes alive at 7-8.
Question: How many touchdown passes did Philip Rivers have?
Answer: 4