By Skip Wood, USA TODAY SAN DIEGO — Kansas City Chiefs quarterback Trent Green gets knocked down hard to the ground. Bam! There he goes again. Then it's Chiefs running back Priest Holmes' turn — and down he stays for a minute or so. For San Diego Chargers rookie linebacker Shawne Merriman, the team's No. 1 pick (12th overall), Sunday's much-needed AFC West win also represented a welcome dose of self-validation. Despite solid play the last few games, Merriman believed he needed to do more, both to help his team and regain a certain feeling of reckless empowerment he hadn't really felt since the season before at Maryland. So when the day was done, when he had the two sacks and several other play-wrecking rushes, Merriman was as happy as he was relieved. "Whenever you're a top draft pick, you have to come out and make plays," he said shortly after the 28-20 win that keeps 4-4 San Diego in the division hunt. "I mean, that's what they got you in for, that's why you go early." Not since Chris Mims had three sacks in 1992 had a Chargers rookie recorded at least two. Merriman's pass-rushing pressure appears to be becoming a staple of the San Diego defense after he was unable to contribute much the first month of the season because of a sore knee. But his first career sack resulted in a fumble by the Pittsburgh Steelers. He forced an interception from the Oakland Raiders' Kerry Collins. He had a sack against the Philadelphia Eagles. And then came his performance this past weekend. Chargers coach Marty Schottenheimer enjoys watching Merriman's flower slowly bloom. "He's making really good progress. He's a very bright young man," Schottenheimer said. "I had a discussion with him the other day, asking him about a blocking scheme. I put it up and asked him who blocks him in a certain play, and right away he knew who blocked him. ... "He has size, he has speed and he has a relentless nature about him, and those qualities make terrific defensive players." Merriman also has fellow rookie Luis Castillo on his unit, a lineman taken with the 28th pick who has been effective at end. He picked up his first career sack against the Chiefs and contributed to another. "Castillo comes out every week and just plays. He has a motor that never stops," Merriman said. "Him and the rest of our D-line just provides a great tempo for us." For his part, Castillo shares Merriman's sense of responsibility. "I think we made our statement today," Castillo said. "It's something where we are both starting and getting the opportunity to get into games and make big plays when it counts. That's what we live for."