By Brian Homewood BASEL (Reuters) - Switzerland struck twice in quick succession to stun Euro 2016 champions Portugal 2-0 in a World Cup qualifier on Tuesday and hand them a first competitive defeat in two years under coach Fernando Santos. Ninteeen-year-old Breel Embolo headed Switzerland ahead in the 23rd minute and Admir Mehmedi doubled the lead six minutes later as Portugal's defence, almost impregnable in France in June, dramatically unravelled. Portugal, missing talismanic forward and record scorer Cristiano Ronaldo, regained their composure and dominated the rest of the game but were hopelessly ineffective in attack. Nani was the biggest culprit when he headed Ricardo Quaresma's cross against the post from close range in the 82nd minute. The Portuguese had 27 attempts on goal to Switzerland's eight but only four were on target. They had 12 efforts blocked and 11 went wide while they also won 11 corners to one for the hosts. Santos was appointed coach in September 2014 and had not lost in 14 competitive games, seven in Euro 2016 qualifiers and seven in the tournament itself. Swiss midfielder Granit Xhaka was sent off for a second bookable offence in stoppage time as tempers flared. "In the first 20 minutes, the Swiss were completely over-run but they scored a goal and from then on, used the tactics that Portugal often use and defended well," Santos told reporters. "Our opponents were more pragmatic and more efficient." "I am sure we will start winning and winning and winning... and I'm convinced we will be at the World Cup." In addition to Ronaldo, still recovering from the injury he suffered in the Euro 2106 final, Portugal were missing key midfielder Renato Sanches while the Swiss were without their top forward, Xherdan Shaqiri. The visitors looked comfortable until Switzerland won a free kick in the 23rd minute. Ricardo Rodriguez produced a fierce effort which goalkeeper Rui Patricio could only parry and Cameroon-born Embolo nipped in to score from the rebound. Portugal were still recovering from that shock when Haris Seferovic got free on the right six minutes later and cut the ball back into the middle of the area where Mehmedi, unmarked, placed his shot into the far corner. Portugal brought on Joao Mario and Andre Silva at halftime and continued to press forward but a series of shots went either over the bar and were fired at Swiss defenders. Bernardo Silva had a scuffed shot easily saved by Yann Sommer and Raphael Guerreiro sent another over. Portugal continued to dominate until the end when Quaresma had a shot deflected over the crossbar and Joao Mario fired into the side netting. (Writing by Brian Homewood, editing by Ed Osmond and Toby Davis)