The N.F.L. playoff picture became much clearer on Sunday, with the Patriots, Raiders and Cowboys all tightening their grips on the top spots. Elsewhere, the Packers threw a wrench in the Lions’ plans in the N.F.C. North, and the A.F.C. South is still a mess. Here’s what we learned in N.F.L. Week 15:

■ There is no quarterback controversy in Dallas.

■ Tom Brady can win in Denver, but that doesn’t mean it will be pretty. The Patriots’ quarterback came into the game with a 2-7 record on the road against the Broncos (his season ended there in two of the last three seasons), but New England held onto the No. 1 seed in the A.F.C. with a boring victory. More good news for the Patriots: they probably won’t have to face Denver in the playoffs because the Broncos’ season is unraveling quickly.

■ For the first time, fans can post on social media that the Oakland Raiders have qualified for the playoffs. It was 2002, long before Facebook, Twitter or even MySpace, when the Raiders last played a playoff game, but with a win over the San Diego Chargers on Sunday they secured a trip to the playoffs, have a lead in their division, and still have a chance at home field advantage throughout the playoffs. More importantly, the team’s defense secured the victory, which could portend good things going forward.

■ The A.F.C. South is still the ugly duckling division of the N.F.L., with the underwhelming Houston Texans continuing to lead the way (by virtue of a tiebreaker over Tennessee) after Sunday’s win over Jacksonville. The Titans may not be much more fun to watch than Houston, but their upset victory over Kansas City would seemingly indicate that they are the superior team.