Paul Thomas Anderson won the top prize at the 78th Directors Guild Awards, putting the “One Battle After Another” filmmaker on course to potentially win his first Oscar. The DGA Awards, held Saturday night at the Beverly Hilton in Beverly Hills, California, is among the most reliable Academy Awards precursors. In the last 10 years, nine DGA winners have gone on to win best director at the Oscars. In the guild’s nearly eight-decade history, only eight times has the guild not predicted the Oscar winner. The award adds to a virtual awards-season sweep for “One Battle After Another,” the best-picture front-runner.