Go figure. It was one of those days for the Rams, and there have been a few of them this year. Days when the Rams get off to an unexpected big lead. It happened against Jacksonville, when the Rams led 24-10 at the half. It happened in Houston, when the Rams led 17-6 at halftime and 38-6 at the end of three. And it happened in Indianapolis, when the Rams led 28-0 at halftime and 38-0 midway through the third quarter. On Sunday, it happened against one of the NFC’s elite teams, the Saints. Pounding the ball on the ground and getting effective and accurate passing from Kellen Clemens, the Rams stunned the Saints early by jumping to a 24-3 halftime lead. Despite the best of efforts by New Orleans quarterback Drew Brees, that lead was too much to overcome. The Rams (6-8) sprung a huge upset, toppling the Saints 27-16 Sunday before 58,442 at the Edward Jones Dome. That dropped the Saints to 10-4, leading to a showdown next week against Carolina, which improved to 10-4 with a 30-20 victory over the New York Jets. Rams running back Zac Stacy, who had only 97 yards rushing combined the past two Sundays against San Francisco and Arizona, had 106 yards and a touchdown by halftime. That set a Rams rookie record for yards rushing in the first half. Meanwhile, Clemens was 10 for 13 with two TDs and a passer rating of 142.0 at the intermission. The defense chipped in as well. On New Orleans’ first offensive play of the day, Robert Quinn hit Brees just as Brees was releasing the ball. Rookie safety T.J. McDonald grabbed the underthrown pass for his first NFL interception. The Rams took over at the New Orleans 31, and on the next play, Clemens threw a short pass in the flat to tight end/fullback Corey Harkey. Harkey, a second-year player, had only eight NFL catches on his resumé entering Sunday’s game. But he turned his ninth into his second NFL touchdown, bull-dozing his way down the right sideline for a 7-0 Rams lead. Harkey, 6-4 and 260, shrugged off a low tackle by safety Malcolm Jenkins and then made cornerback Corey White miss en route to the end zone. Harkey’s previous long reception had been 21 yards as a rookie in 2012.