- Lars Bender rattles the post with a powerful effort from distance
- Miroslav Klose hits the woodwork at the other end with Lazio's best first-half opening
- Keita gives Lazio slender advantage to take with them to Germany
- The sides meet in the return at the BayArena in Leverkusen on 26 August
Lazio will take a one-goal lead to Germany after coming out on top in an entertaining UEFA Champions League play-off first leg in Rome, which Keita's powerful surge and neat finish won.
Leverkusen, with one Bundesliga game already in their legs, had more of a spring in their step to begin with, but Lazio – whose Serie A campaign commences at the weekend – soon responded and produced the first chance of the match when Lucas Biglia's shot was deflected over.
Karim Bellarabi went a touch closer at the other end before some brave defending from Maurício scuppered Son Heung-Min's hopes of opening the scoring. The frenetic pace continued with Lars Bender going the closest yet with a 30-metre effort rattling the upright.
Stefan de Vrij vies with Stefan Kiessling
Before the midfielder's hands could drop from his shocked head, Miroslav Klose was hitting the post at the other end, having rounded Bernd Leno only to find the angle just too tight to squeeze the ball in.
Hakan Çalhanoğlu mustered the first shot on target of the night after an hour's play, but while his direct free-kick found its way through the Lazio wall, it did not beat Etrit Berisha's fists.
At the other end, the lively Keita wasted another Lazio opportunity before fellow half-time substitute Admir Mehmedi flashed an attempt centimetres wide of the far post. Hakan thought he had made the breakthrough with 20 minutes remaining, yet his effort clipped Stefan Kiessling's calf on its way in with the Leverkusen forward in an offside position.
There was no let-up with both teams chasing a winner, and Lazio found it with Keita bursting through before slotting his low shot in off the inside of the far post, giving the Biancocelesti a slender advantage to take with them to Germany.
Stefano Pioli, Lazio coach
It was a difficult and complicated match. Leverkusen played direct and aggressive football. We made some mistakes, but playing Leverkusen is not easy. We could have scored more but the result is certainly positive. The result does not change much for the return leg – there is still a battle to be fought. Lazio want to play in the UEFA Champions League and we showed that tonight too, but we have to improve if we want a positive result at the BayArena next week.
Roger Schmidt, Leverkusen coach
It was an intense match. We had several opportunities to score, but we weren't able to do so. However, Lazio did – they have a strong team. Now we have the return match where we will try to overturn this result. Ahead of the home tie, we will work on our counterattacking and on our defensive game – we will do our best. We have worked well in recent weeks and we are pretty confident [of progressing].