There wasn&rsquo;t much to say. The big plays happened, the Chiefs were blown out, and a group of discouraged and overmatched defenders struggled to explain why.</p><p>San Diego used six plays that gained at least 20 yards, including two 51-yarders that made Kansas City&rsquo;s secondary look bad &mdash; and the team&rsquo;s locker room look discouraged and confused after the Chargers&rsquo; 37-7 walloping at Arrowhead Stadium.</p><p>&ldquo;That was pretty embarrassing,&rdquo; Chiefs cornerback Brandon Carr said. &ldquo;To get beat by that large margin.&rdquo;</p><p>For the first three quarters, before San Diego finally let off the accelerator, the Chiefs looked disorganized, confused and out of place against the Chargers&rsquo; talented offense. And for the second time in three weeks, Kansas City made a temporary superstar out of a lower-profile wide receiver.</p><p>Fourteen days earlier, it was Dallas&rsquo; Miles Austin, the pride of Monmouth University, who had 250 receiving yards and two touchdowns in a win against the Chiefs. On Sunday, it was Vincent Jackson, the talented but largely unknown San Diego wide receiver, who burned the Chiefs for both of those 51-yarders. He finished with 142 yards receiving and a touchdown. </p><p>Quarterback Philip Rivers kept looking to Jackson, and Jackson kept torching the Chiefs. Kansas City&rsquo;s defensive backs couldn&rsquo;t explain it. It just kind of happened.</p><p>&ldquo;Just a lot of letdowns,&rdquo; Carr said. &ldquo;Any big play is deflating, but a good defense can bounce back, come back out on the next drive and make a play to get off the field.&rdquo;</p><p>Whatever Carr&rsquo;s statement meant about the state of Kansas City&rsquo;s defense, one fact is clear: A perceived strength for the Chiefs, their young secondary, has proved to be as porous and inconsistent as the rest of this team. Carr kept running to catch up with streaking receivers, and strong safety Mike Brown kept taking odd angles to pursue ball carriers. </p><p>When it was over, only Carr was willing to offer reasons why. Brown wouldn&rsquo;t answer questions about the defense&rsquo;s shortcomings, cornerback Brandon Flowers said through a team spokesman that he wouldn&rsquo;t speak to reporters, and free safety Jon McGraw was in the training room during the time reporters were allowed in the locker room. </p><p>Carr said he took comfort that, at least in one way, the Chiefs&rsquo; defense showed promise. The team executed two goal-line stands, twice stuffing San Diego&rsquo;s talented running backs near the goal line. But if that showed progress, the secondary&rsquo;s sour contribution Sunday overshadowed it. </p><p>&ldquo;We just didn&rsquo;t make plays when we needed to,&rdquo; defensive end Glenn Dorsey said. &ldquo;Just missed tackles and missed contains. You can&rsquo;t do that. Their team has got a lot of good weapons. We just didn&rsquo;t do what we needed to do.&rdquo;