The Green Bay Packers won a shootout with the San Diego Chargers, 45-38, at Qualcomm Stadium in San Diego, CA. San Diego received the opening kickoff and QB Philip Rivers navigated the Chargers down the field and found WR Vincent Jackson for a 23-yard touchdown early in the first quarter. Then Packers QB Aaron Rodgers took the field and did the same finishing the 8 play, 63-yard drive with a 5-yard touchdown pass to TE Jermichael Finley to tie the score 7-7. Then the Green Bay defense went to work. On consecutive drives the Packer defense picked off Rivers and returned it for touchdowns, the first a 40 yarder by SS Charlie Peprah and the latter, a 43 yarder by CB Tramon Williams. In the blink of an eye, it was 21-7 Green Bay. San Diego answered with another touchdown drive of their own completed by RB Michael Tolbert 8-yard run. San Diego K Nick Novak booted a 52-yard FG to cut the GB lead to 4 but Rodgers hooked up with WR Jordy Nelson for a 16-yard score just 18 seconds before halftime and took a 28-17 lead into the locker room. The second half got under way and Green Bay navigated its way down the field and K Mason Crosby converted a 47-yard FG to remain a perfect 15-15 on the season. Rivers threw his second touchdown of the game to TE Antonio Gates late in the third quarter to cut the Packer lead to 31-24. Green Bay appeared to put the game out of reach early in the fourth quarter when Rodgers threw touchdown passes to WR James Jones and WR Greg Jennings, as the Packers led by 21. But San Diego once again stormed back when Jackson caught his second touchdown of the day which was followed by a San Diego onside kick and recovery. San Diego wasted no time as under a minute later Rivers found Jackson for the third time and suddenly it was 45-38 with over six minutes to play. That was the final score as the Packers Charlie Peprah made his second interception to seal the victory for Green Bay. Rodgers finished the day 21/26 for 247 yards with 4 touchdowns and no interceptions for Green Bay. Rivers finished 26/46 for 385 yards with 4 touchdowns but 3 big interceptions for San Diego. With the win Green Bay improves to 8-0 at the midway of the season and host division rival Minnesota next Monday on Monday Night Football at Lambeau Field. San Diego falls to 4-4 and have a quick turnaround as they host Oakland on Thursday in the 2011 first edition of NFL Network's Thursday Night Football.
Question: How many of Rivers' passes were incomplete?
Answer: 20