Steady Manning, solid defense keep Giants winning

EAST RUTHERFORD, N.J. — Five things worth knowing from the New York Giants’ 29-17 victory against the San Francisco 49ers on Sunday at Giants Stadium:

1. On edge

It is becoming apparent that despite their league-leading total of 15 sacks after three games, the Giants do miss injured Osi Umenyiora and retired Michael Strahan at defensive end. After failing to get a sack in their 35-14 loss to the Browns Monday night, defensive end Dave Tollefson sacked quarterback J.T. O’Sullivan for a 3-yard loss on the 49ers’ third play from scrimmage. But the Giants’ other two sacks in the first half came from defensive tackles Fred Robbins and Barry Cofield and were achieved only after O’Sullivan could not find an open receiver downfield.