FT: Slovakia 1 Scotland 0
Scotland's nine-match unbeaten run came to an end with a 1-0 defeat against fellow Euro 2020 qualifiers Slovakia.
A deflected long-range first-half effort from Jan Gregus prevented a much-changed Scotland side from equalling their longest run without defeat since 1927.
A Scotland win would have secured top spot in Nations League Group B2 - and potentially one of two World Cup play-off places on offer from the competition.
Steve Clarke's men had plenty of chances in Trnava. Oli McBurnie endured more frustration in pursuit of his elusive first international goal and Kenny McLean was denied by a brilliant second-half stop before substitute Leigh Griffiths was denied twice in stoppage-time.
Scotland will still win the group if they beat Israel on Wednesday and could even clinch it later on Sunday - if Israel and Czech Republic draw.
Clarke made eight changes following his side's penalty shoot-out Euro 2020 play-off win in Serbia having stressed beforehand that their post-match celebrations would have no bearing on his selection.
Only Kieran Tierney, Ryan Christie and John McGinn, who was named captain, kept their places while Craig Gordon, Scott McKenna, Liam Cooper, Andy Considine, Liam Palmer, Kenny McLean, Stuart Armstrong and McBurnie came in.
Skipper Andy Robertson dropped out of the 23-man squad because of a tight hamstring along with the suspended Lyndon Dykes.
Gordon palmed away Juraj Kucka's swerving shot six minutes in before Scotland created a flurry of chances.
Christie saw an angled drive saved following an Armstrong pass before setting up McBurnie, whose first touch let him down. The loose ball fell to Palmer whose shot arrowed over the bar.
Tierney took an elbow to the face in the Slovakia box but was penalised for the challenge before Armstrong presented McBurnie with another chance only for the Sheffield United striker to take too long to shoot.
Armstrong curled a free-kick over before being booked for holding his ground in an aerial challenge. He now misses the game in Israel on Wednesday through suspension.
Scotland continued to look confident and comfortable but fell behind in the 31st minute.
Gregus was allowed too much time to line up a shot from 25 yards and the ball deflected off McLean to give Gordon no chance as the shot nestled in the bottom corner.
Scotland kept on creating chances. Palmer shot over first time from Tierney's delivery before crossing for McBurnie, who got in front of his marker but headed straight at the goalkeeper from 10 yards.
Christie then sent Armstrong away down the left channel with the home keeper slow to get out, but the Southampton midfielder could only dink the ball across the face of goal from a tight angle.
Slovakia got tighter to Scotland in their own half after the break and had some sporadic long-range efforts but the visitors continued to threaten at times.
McLean could not wrap his foot around Armstrong's driven cutback before forcing a brilliant stop from Marek Rodak when he powerfully headed Tierney's cross towards the corner.
Clarke made a tactical switch midway through the half as Griffiths replaced centre-back Considine to move to a 4-4-2.
The hosts immediately played their way through Scotland's defence for the first time but Gordon got down well to deny Michal Duris.
Scotland exerted some late pressure. Armstrong saw a shot deflected wide and McBurnie almost set up Griffiths only for a covering defender to clear the danger.
Too many crosses failed to find their target as Slovakia defended their box before Griffiths had chances in the closing moments.
A curling effort from 25 yards was well held before the striker burst into the box following a long ball, but Rodak produced a superb one-handed stop to divert his powerful strike.