How PFF graded McCaffrey, 49ers offense’s historic performance

The 49ers had an incredibly efficient performance in their 35-16 win over the Arizona Cardinals on Sunday at Levi's Stadium, and their PFF grades reflect how productive they really were. San Francisco quarterback Brock Purdy connected on all but one of his 21 pass attempts. His 20 completions added up to 283 yards, one touchdown and a 134.6 passer rating. Purdy's 95.2 percent completion rate broke a franchise record held by Steve Young (90 percent; minimum 20 attempts) since 1991. Purdy's average depth of completion yesterday was 9.1 yards downfield, which is the second highest among NFL quarterbacks in Week 4 through Sunday's games. The second-year play-caller continues to be extremely accurate in intermediate level passes (11 to 19 yards), completing all three attempts for 61 yards for a 91.7 percent completion rate through four games. Where Purdy was less accurate was on deep passes but on Sunday, the quarterback showed why there shouldn't be any doubt. Purdy completed all three of his pass attempts that traveled more than 20 yards in the air. Purdy received a lot of support during the game from Christian McCaffrey, who also had a historic performance. The running back's 13th...