Portugal all but sealed a berth in the Nations League quarter-finals with a 0-0 draw away to Scotland on Tuesday, the first points Roberto Martinez's side have dropped in their four games.
The Portuguese remain top of Group A1 with 10 points, three ahead of Croatia, who drew 3-3 away to Poland, while the Scots are bottom on one point. The third-placed Poles have four points with the top two in the group moving into the last eight.
Portugal were on the front foot for most of the night but squandered chances including a sitter early in the second half for Cristiano Ronaldo, who had scored in their previous three games. Unmarked in the box, heput a diving header over the bar.
The 39-year-old Ronaldo earned another ironic cheer from Scotland's "Tartan Army" when he sent a bicycle kick wide.
The hosts also had chances on a night when they were plagued by careless turnovers as Scott McTominay narrowly missed with a header before the game was five minutes old.
Ben Doak laid the ball back to Andy Robertson and the captain found the unmarked McTominay with a pinpoint cross but the midfielder headed it straight at goalkeeper Diogo Costa.
Scotland keeper Craig Gordon made a handful of terrific saves in the dying minutes against a swarming Portugal side.
The Hampden Park crowd erupted when Gordon dived to block a shot from Bruno Fernandes and then corralled the ball before Ronaldo could get there for the rebound.
Right back Nicky Devlin came on for his Scotland debut in the 89th and was pressed into action minutes later when he made a brilliant block to deny Rafael Leao.
Ronaldo was irate at the final whistle when he was denied the chance to take a corner with the clock having ticked past four added minutes. He ranted to the referee and gave the home fans a double thumbs-down before storming off the pitch.
At least a draw at home to Poland on November 15 would guarantee Portugal a place in the knockout round before they visit Croatia three days later in their final group game.
While a point snapped Scotland's four-game losing run, they have gone 10 games without a victory in competitive matches.