Jon Gruden’s return to the sidelines didn’t go so well for the Oakland Raiders head coach. The second act of the season doesn’t look any easier.Gruden left the ESPN booth early this year to take over the Raiders again, and his much-hyped debut was thwarted in a 33-13 loss to the Los Angeles Rams on Monday. Now Gruden’s Oakland team travels to Denver to play the Broncos on Sunday. Denver is coming off a 27-24 win over Seattle in its opener and feeling good, despite having three turnovers against the Seahawks.Head coach Vance Joseph nonetheless wants to correct those mistakes – three interceptions of Case Keenum in his Denver debut – and some defensive breakdowns.”It’s good to win, but we do have standards, and our standards can’t be measured by who we play. It’s got to be by how we play,” he said. “Yes, we’re satisfied to win but we understand it’s a long year. It’s only Week 1 and we’re going to play good teams down the road. We can’t play that way and expect to win every game by giving the ball away three times and giving up five explosive plays. It’s can’t happen.”At least the Broncos (1-0) are correcting things after a win. Oakland (0-1) was routed on national TV and quarterback Derek Carr had a bad statistical game. He threw for 303 yards but was intercepted three times, once on a floater that easily was picked off late in the game.He was given another weapon with the signing of wide receiver Martavis Bryant, who was cut before the start of the season. Oakland traded a third-round pick to Pittsburgh in April for the mercurial receiver, but he was brought back because of a game-breaking ability that seemed lacking against the Rams.