United are currently second in Group A, level on points with Shakhtar Donetsk despite a better goals scored tally; however, Mircea Lucescu's men are top as they have scored more away goals (two at Real Sociedad, compared to the Reds' one in Donetsk).
Real Sociedad prop up the group in fourth place without a point to their name, but 35-year-old boss Jagoba Arrasate hopes that, after a 2-1 La Liga win over Valencia at the weekend, they have turned a corner after a challenging start to the season.
United's results have also been mixed in a tough opening to the Reds' domestic campaign, but in Europe David Moyes' men have performed admirably, beating Bayer Leverkusen 4-2 and earning a 1-1 draw in Donetsk.
"We have done well [so far]," says Rafael in an exclusive interview with United Review. "We were pleased with our performance against Bayer Leverkusen and then it was important to come away from Donetsk with a good result. We managed to do that. We have played some good football in the competition so far and we want to keep that going."
The meeting with La Real provides an opportunity to notch three vital points toward qualification for the knockout stages. "It is a great chance for us," adds Rafa. "We need to win the game to give us confidence for the match in Spain. That's all we're focused on.
"They will come here to win. Spanish teams aren't the type to sit back and defend. They will always attack. They were close to getting a draw at Leverkusen [they lost 2-1 after an injury-time winner] and that will have given them encouragement."
Read the exclusive interview with Rafael in the Real Sociedad edition of United Review, the official matchday programme. Buy it at OT for