The top-seeded Spain's Carlos Alcaraz eased past Daniel Evans 6-2, 6-2 to reach the final of Barcelona Open, where he is bidding to become the first repeat champion since Rafael Nadal lifted the trophy three years in a row from 2016-18.
The Barcelona Open is one of the most important events in Spanish tennis with Rafael Nadal having won the title 11 times.
Murray will next face Austrian fourth seed Dominic Thiem for a place in the final.
Albert Montanes thanked his fans for always showing support and giving him strength.
Indo-Uruguay pair lost 6-7 (3) 6-7 (2) to the combination of Henri Kontinen and John Peers.
This latest defeat means the 35-year-old veteran has lost yet another match in a disappointing season.
Zverev took two hours and 26 minutes to defeat World No. 57 Almagro 7-6 (7-4), 4-6, 6-4.
Barcelona Open's organising committee confirmed the participation of the Spanish tennis star Rafael Nadal in next year's edition of the tournament.
