Birkirkara therefore failed to take advantage of the draw between Balzan and Valletta on Saturday after claiming maximum points from their first three matches.
The Wanderers had three changes as Aidan Friggieri, Beppe Muscat and Salomon Wisdom replaced Roger, Peter Xuereb and Jean Paul Farrugia. On the other hand, Birkirkara coach Drazen Besek retained the same players who had started the last game against Hamrun.
Sliema took the lead just before half-time as one minute in added time they were awarded a penalty after Joseph Zerafa brought John Mintoff down inside the area; from the penalty spot, Alex Muscat converted.
The Wanderers doubled the score on the 76th minute when a shot by Mathias Muchardi from the right was partially saved by Kopric and off the rebound, Michel Wisdom Salomon Aka placed the ball at the back of the net.
Birkirkara reduced the gap four minutes later thanks to Frank Temile whose close range shot from the left beat substitute goalkeeper Glenn Zammit.
SLIEMA Giuseppe Sarao (32′ Glenn Zammit), Alex Muscat, Gary Muir, Aidan Friggieri (84′ Armando Vieira dos Santos Tarlazis), Beppe Muscat, Michel Salomon Wisdom, Mathias Muchardi, John Mintoff, Mark Scerri, Milos Galin (62′ Jean Paul Farrugia), Marko Potezica.
Subs not used: Gabriel Aquilina, Michele Sansone, Ryan Spiteri, Peter Xuereb.
Coach: John ButtigiegB’KARA Miroslav Korpic, Gareth Sciberras, Mislav Andelkovic (46′ Rowen Muscat), Srdjan Dimitrov, Vito Plut, Nikola Vukanac, Frank Temile, Joseph Zerafa, Ryan Scicluna, Cain Attard (46′ Shaun Bajada), Predrag Jovic (69′ James Brincat).
Subs not used: Ini Etim Akpan, Edward Herrera, Matthew Guillaumier, Steve Bonnici.
Coach: Drazen BesekReferee: Esther Azzopardi
Assistant Referees: Duncan Sultana, Thomas Debono
Fourth Official: Fyodor Zammit
Yellow Cards: Zerafa, Scerri, Mintoff, Zammit
BOV Player of the Match: Mathias Muchardi
Attendance: 1,292