BERLIN, March 20 (Xinhua) -- Mainz 05 secured their place in the Conference League quarterfinals after a 2-0 home victory over Sigma Olomouc in Thursday's second leg, sealing progression following a goalless first leg.

Mainz coach Urs Fischer introduced three changes to his lineup from the first leg, with Nelson Weiper, Lee Jae-sung and Silvan Widmer coming in.

The hosts immediately imposed themselves, pinning the visitors back and creating early chances through Phillip Tietz and Weiper, both denied by Jan Koutny. Despite sustained pressure and numerous deliveries into the box, Mainz struggled to produce a decisive finish before the interval.

Phillipp Mwene came closest with a curling attempt that drifted narrowly wide, while another effort before the break failed to test the goalkeeper.

Mainz needed only moments after the restart to make their dominance count. Paul Nebel delivered from the right and Stefan Posch rose centrally to guide a header into the far corner in the 46th minute.

The hosts remained in control but found limited space in the final third before Da Costa set up Armindo Sieb, who finished into the far corner in the 82nd minute to secure the result.

Olomouc offered little response thereafter as Mainz managed the closing stages without difficulty. ■