The Redskins barely survived their game against the 49ers on Sunday for a third win in their pockets. Based on the first half, it should have been a relatively clear path to victory. But it also could have easily gone the other way, like their almost-win against the Chiefs two weeks ago, which ultimately became their second loss.

If there was a pattern in the two games, it was the Redskins’ inability to build on early success. Against the Chiefs, they led 10-0 in the first quarter and were outscored 29-10 the rest of the way. Sunday, the lead was 17-0 with 1:51 left in the first half. but after that, they were outscored 24-9.

In fact, the Redskins have built up double-digit leads before the other team got on the scoreboard in each of their last four games. They led the Rams 13-0 and the Raiders 21-0. In three of those four games — every one except for the Raiders game — the Redskins let the opposition move into at least a tie.

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I’m old enough to remember the preseason, when there was much handwringing over the offense getting off to slow starts. In five regular season games, the Redskins have outscored the opposition by 27-7 in the first quarter and 75-40 in the first half. (Everyone should now nod and say the preseason means nothing, and everyone will remember that right up until the first preseason game of 2018 kicks off).

But the Redskins apparently can’t stand the prosperity. They have been outscored 73-42 in the second half.

If you look at the numbers, a lot of the second-half drop off is about the running game. In the first half, the Redskins have rushed for 375 yards with a strong average of 4.8 yards per carry. After intermission, they have 237 yards and an average of 3.4 per attempt. It should be noted that Jay Gruden is not abandoning the run. They have run 79 times in the first half and 70 in the second — hardly a statistically significant difference on a fairly small sample size.

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The Redskins also become easier to run against in the second half. Opponents have 162 yards rushing with a 3.2 average in the first half and 237 with a 4.0 average after that.

It’s not as simple as that, of course. There are moments of defensive lapses — like when coverage broke down and former Redskins receiver Aldrick Robinson was able to get wide open to catch a 45-yard touchdown pass from a scrambling C.J. Beathard, and when Alex Smith scrambled to his right and completed a pass that set up the winning field goal. The Redskins defense needs to play better in those moments.

The offense needs to perform better in the second half. That’s when the defense is supposed to be wearing down. The rushing average should go up, not down. The 49ers defense had been on the field for 68 plays when the Redskins recovered that onside kick. They should do better than three runs for six yards and a punt that gave San Francisco a last chance.

There is talk that the Redskins are a better team this year, and there are signs that they are. But if they don’t learn how to finish off their hot starts their record won’t show much improvement.

Stay up to date on the Redskins. Rich Tandler covers the team 365 days a year. Like his Facebook page Facebook.com/TandlerNBCS and follow him on Twitter @TandlerNBCS.