SAN DIEGO, Calif., June 20 (Reuters) - Jon Rahm"s U.S. Open buildup suffered a huge setback when a positive COVID-19 test forced him out of the Memorial tournament when leading by six, but the Spaniard said he was able to keep a positive outlook thanks to advice from major champions Padraig Harrington and Nick Faldo. Rahm, who triumphed by a shot at Torrey Pines on Sunday to win his first major, said both Harrington and Faldo told him they had learned so much through the adversity of being disqualified from tournaments they were set to win. "Padraig told me a story in which he was leading by five after 54 holes, signed the wrong scorecard, and got disqualified," Rahm said. "He said he learned a lot more than he would ever learn from the win. "Nick texted and told me a story of how he was winning a tournament, leading by six with six holes to go and got disqualified, as well, and how he learned from that and got a win the week after." Rahm said their stories stayed with him, and while many of the game"s biggest names crumbled at the U.S. Open the Spaniard stood tall. "I had in mind Padraig and Nick when I was out there on the course a couple times knowing that they won shortly after (adversity), and I knew today was my day," said Rahm, who finished on six-under 278 for a one-shot win over South African Louis Oosthuizen. "I believed from the biggest setbacks we can get some of the biggest breakthroughs, and that"s why I stay so positive. "I kept telling (wife) Kelley, something good is going to come. I don"t know what, but something good is going to come, and I felt it today out there on the golf course." Rahm sank a 10-foot birdie at the first hole, and followed it up with a virtual tap-in birdie at the next to cut a three-shot overnight deficit to one stroke. "I could just tell going down the fairway after that first tee shot, that second shot, and that birdie, I knew there was something special in the air," he said. "I could just feel it ... I just knew that I could do it and believed it."