The victory gave Stuttgart back-to-back wins in the Champions League league phase, strengthening their position as they continue their European campaign under head coach Sebastian Hoeneß.
Undav puts Stuttgart ahead
Stuttgart gradually took control after an energetic start from the hosts, who initially threatened through Tigran Barseghyan. Goalkeeper Fabian Bredlow dealt with the early effort before the visitors began creating opportunities of their own.
The breakthrough arrived in the 29th minute when Angelo Stiller played a precise pass into the penalty area for Undav. The forward controlled the ball and finished into the bottom corner, giving Stuttgart a deserved lead.
Josha Vagnoman came close to doubling the advantage shortly afterwards, but his powerful volley struck the crossbar. Stuttgart continued to threaten before the interval, with Slovan goalkeeper Dominik Takáč making important saves to keep the deficit to one goal.
VAR denies Slovan Bratislava an equaliser
Slovan attempted to respond after the restart and briefly appeared to have drawn level through Suleiman Sanneh in the 53rd minute. However, the goal was ruled out for offside following a VAR review.
Sanneh threatened again in the 61st minute, striking the crossbar as the Slovakian side searched for an equaliser.
Stuttgart subsequently regained control and delivered a decisive second goal in the 65th minute. Vagnoman sent a dangerous ball across the penalty area, and defender Sandro Cruz inadvertently diverted it into his own net to make it 2-0.
Demirović completes the victory
With Stuttgart protecting their two-goal advantage, Slovan struggled to find a route back into the contest. The visitors remained organised and continued to look dangerous as the match approached its conclusion.
Substitute Lorenz Assignon provided the decisive delivery in the 90th minute, sending a cross into the penalty area for Demirović to head home from close range.
The late goal completed a comfortable 3-0 away victory for Stuttgart, underlining their attacking threat and ability to manage the closing stages of a European fixture.
Stuttgart maintain perfect Champions League start
The result marked Stuttgart's second consecutive victory in the Champions League league phase. They had opened their campaign with a 3-1 win against Viking Stavanger before following it up with another three-goal performance in Bratislava.
For Slovan Bratislava, the defeat represented another difficult European outing after their opening 6-1 loss to Paris Saint-Germain.
Stuttgart will look to build on their positive start as the league phase continues, while Slovan must improve defensively and convert more of their opportunities to revive their campaign.
Match details
Goalscorers
• VfB Stuttgart: Deniz Undav 29', Sandro Cruz (own goal) 65', Ermedin Demirović 90'
• Slovan Bratislava: No goals