Whatever Alonso said at halftime clearly worked.
Atalanta are in the last four of a European competition for the first time since 1988.
Daniele De Rossi will stay on long-term as Roma coach, the Serie A club announced on Thursday, hours before their Europa League quarter-final decider with AC Milan.
Jonas Hofmann and Victor Boniface scored after coming off the bench as Bayer Leverkusen beat West Ham 2-0 at home on Thursday in their Europa League quarter-final first leg.
Atalanta stunned Anfield as Gianluca Scamacca scored twice in a 3-0 win on Thursday to leave Liverpool with a mountain to climb to reach the Europa League semi-finals.
AC Milan, Marseille, Roma and West Ham were among the other sides to also book their place in Friday's quarter-final draw.
The draws for the last 16 of both competitions will be made at UEFA headquarters in Nyon on Friday.
AC Milan, meanwhile, were drawn against French club Rennes.
Whatever Alonso said at halftime clearly worked.
Atalanta are in the last four of a European competition for the first time since 1988.
Daniele De Rossi will stay on long-term as Roma coach, the Serie A club announced on Thursday, hours before their Europa League quarter-final decider with AC Milan.
Jonas Hofmann and Victor Boniface scored after coming off the bench as Bayer Leverkusen beat West Ham 2-0 at home on Thursday in their Europa League quarter-final first leg.
Atalanta stunned Anfield as Gianluca Scamacca scored twice in a 3-0 win on Thursday to leave Liverpool with a mountain to climb to reach the Europa League semi-finals.
AC Milan, Marseille, Roma and West Ham were among the other sides to also book their place in Friday's quarter-final draw.
The draws for the last 16 of both competitions will be made at UEFA headquarters in Nyon on Friday.
AC Milan, meanwhile, were drawn against French club Rennes.