Spain failed to secure automatic qualification for the 2019 rugby World Cup on Sunday, losing to Belgium 18-10 with their players rounding on the Romanian referee who had to be escorted off the pitch.
They next face Portugal with the victor going on to play Samoa in a two-legged play-off for a ticket to join hosts Japan, Grand Slam champions Ireland, Scotland, and the Romanians in Pool A.
Spain players blamed the Romanian referee on Sunday for their team's failure to automatically qualify for the 2019 Rugby World Cup.
Spanish players confronted referee Vlad Iordachescu, a Romanian, at the final whistle in their loss to Belgium.
Rugby Europe, the organisation responsible for allocating officials, also made a statement on Monday: "Rugby Europe Selection Committee is waiting for the assessment report of the Supervisor for Belgium v Spain Match officials".
Spain's rugby federation had shown pre-match concern over the appointment of Romania referee give the importance of the match but there complaints were ignored.
Spain was in pole position for qualifying after it beat Romania 22-10 in Madrid last month for the first time in six years.
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Dusan Tadic's corner was stabbed goalwards by Hojbjerg and Wigan's Dan Burn couldn't react quick enough to clear off the line. Subs: Nathan Redmond (for Boufal, 65) 6, Shane Long (for Carrillo, 81) 6, Oriel Romeu (for Gabbiadini, 88) 5.
"It isn't just Spain who are the losers today", Santos told LaLiga4Sports.
He then offered his apologies to the ref for his side's actions, adding: "I am captain and I apologise for the persecution of the referee".
The referee was appointed by REC, not World Rugby.
The Spanish Rugby Federation (FER) apologised on its website, saying it "regrets the reaction of some players who did not contain their mood at the end of the match".
"It has been reviewed and confirmed during the tournament based on referees' performance at worldwide level".
"The difference between penalties against us and for us was huge", Santos said. "When we were trying to come back in the game the play kept on being interrupted".
"While we appreciate that this is a subject of high-emotion, it would be inappropriate to comment on match official performance before the usual full review has been undertaken".