Write a question about the following article: San Diego took the lead late in the second quarter when Philip Rivers threw a TD to WR Vincent Jackson, giving San Diego a 7-0 lead going into halftime. Rivers had a bad first half completing only 1 of 10 passes, the only completion being a touchdown. The 3rd quarter saw San Diego add to their lead making it 10-0. But Seattle RB Shaun Alexander narrowed the gap with a rushing TD making it 10-7, San Diego would answer back with a field goal to make it 13-7, but on Seattle's ensuing drive they allowed another Alexander TD to make the score 14-13 and they would allow a field goal to give Seattle a 17-13 lead. With time running out San Diego drove down the field and Rivers would connect with a 37-yd pass to Jackson to give the Chargers a 20-17 lead with only&#160;:29 seconds remaining. The defense would hold and the Chargers continued their winning ways setting a team record 13th win. The win also clinched a first round bye and set up the Chargers to control their own destiny the next week against Arizona, as a win would clinch them homefield advantage throughout the playoffs.
How many points was San Diego leading by at the end of the first half?