888Sport offer 40/1 (41.0) about either of these sides winning the tournament. Given the seeded draw which ensures the elite teams avoid each other though, it seems unlikely either will make a deep run this term.
Nevertheless, the home side are 888Sport's 19/20 (1.95) favourites to take a first leg lead in this cup clash. Sociedad can be backed at 16/5 (4.20) to win at Estadio Benito Villamarin while a draw is priced at 11/5 (3.20) with the online bookmaker.
A stalemate makes some appeal given the two-legged nature of this encounter, but the best bet looks to be opposing goals, partly due to the same logic of a cagey clash being the likely outcome.
Both teams boast top 10 defences in La Liga this term. Betis have conceded 21 times in 18 matches while Sociedad rank a goal better in that regard.
Given that neither are especially potent in the final third, it makes sense that we'd see a low-scoring first leg with neither team willing to commit too much forward at a relatively early stage of the tie. Under 2.5 goals at 3/4 (1.75) with 888Sport is therefore a solid option for punters to consider.
This wager has paid out in six of nine Betis home games in the league this season, including a 1-0 win over Sociedad back in early December.
The visitors have seen this bet land in five of their last six matches in all competitions too, so they could be relying on a rear-guard action to continue their Copa Del Rey journey.