Iago Aspas hit the crossbar as Celta Vigo were held to a 0-0 draw in the first leg of their Copa del Rey semi-final tie against Alaves at Balaidos.
Alaves' Manu Garcia forced Sergio Alvarez into an excellent save in an opening half otherwise lacking in drama on Thursday.
Celta were more dominant after the break and Aspas was denied by Fernando Pacheco's superb stop before later striking the woodwork.
Pablo Hernandez then hit the post in a late scramble after Alaves failed to deal with a free-kick as the contest remained evenly poised.
The tie will be decided in the second leg at Mendizorrotza next Wednesday, with the winners facing either Atletico Madrid or holders Barcelona in the final.
Celta – conquerors of Real Madrid in the last eight - have never won the Copa and made the last of their three final appearances back in 2001.
Alaves, meanwhile, have never progressed beyond this stage.
Celta, who made seven changes from their LaLiga win over Leganes, had more of the early possession but neither side mustered an attempt on goal for the first half-hour.
The hosts saw Marcelo Diaz and Facundo Roncaglia have long-range shots charged down, but it was Alaves – unchanged after their league draw with Atletico Madrid - who had the best effort of a dire first half.
Victor Camarasa created the chance with a cross from the right wing that was flicked towards goal by captain Garcia, but he was denied by a brilliant diving save from Sergio.
Theo Hernandez then struck over as the visitors gained some momentum before the break.
Celta were in the ascendancy early in the second period and it was their turn to be thwarted by exceptional goalkeeping, Aspas having a shot crucially saved by Pacheco from inside the six-yard box after Gustavo Cabral had headed a Daniel Wass corner into his path.
Aspas then came even closer, smashing a half-volley against the bar from 18 yards after he had been found by a perfectly weighted header from Wass.
The former Liverpool striker was giving everything to find an opener, first sending a diving header wide from Hugo Mallo's curling cross before just missing the target with an overhead kick.
Alaves almost grabbed a late winner on the break when Camarasa released substitute Edgar Mendez but Sergio got down sharply to keep out the effort from a tight angle.
Celta had one more big chance in them, a combination of Pachecho and the post keeping out Hernandez from close range as there was ultimately no separating the mid-table Liga sides.
