Melvin Gordon ran the ball from the 1-yard line. And then he ran it again. And again. And again. He never got over the goal line, squandering a short field following the Chargers’ fumble recovery at Denver’s 45-yard line. They beat the Broncos anyway, 21-0, but memory of that sequence still left Coach Anthony Lynn fuming on Sunday. “That was absolutely terrible,” Lynn said. “Anytime we have the ball on the 1-yard line and I give it to my back four times in a row, and we don’t get it in — that’s awful.” Denver entered StubHub Center as the only defense in the NFL that had not given up a rushing touchdown. They left Southern California the same way, despite Gordon’s best efforts. That possession highlighted one of the flaws in Gordon’s game. The former first-round pick entered the weekend with a league-high seven touchdowns, but had gotten four of them on catch-and-runs. As dangerous as he is in space, the 6-foot-1, 207-pound back has been less effective between the tackles. After finishing with 38 yards on 18 carries Sunday, his per-attempt average dropped to 3.4 — the lowest single-season mark of his career. Still, the Chargers had no intention of sprinkling in different play calls — not when they were just a short leap away from the end zone. After all, Gordon had scored in a similar situation a week ago, vaulting into the end zone in Oakland. He may have been limited in practice this week by a shoulder injury, but he is still their workhorse.