I don't see Real Madrid losing four matches in the league. Real Madrid's 8-point lead over Barcelona is enough for Real Madrid to win the matches that would make them win the La Liga title without battling with Barcelona over who will win the La Liga title this season. The match between Real Madrid and Athletic Bilbao will be a tough match for Real Madrid because Bibao wants points to remain in the fourth position of the La Liga table. Real Madrid will use home advantage to dominate and win Athletic Bilbao.
I think Real Madrid will not let 4 defeats happen to Real Madrid, Real Madrid has overcome many obstacles to reach the top of the standings and Real Madrid has widened the gap so Real Madrid will not waste this and Real Madrid will continue to achieve victory after victory so the club under it is difficult to overtake, even though in just 29 matches Real Madrid only experienced 1 defeat, whereas this season there are only 9 matches left, of course Real Madrid will get through it and not add to their total losses, but even if Real Madrid makes a mistake and loses, it will not affect its position and These mistakes will not continue to repeat themselves, especially in 4 consecutive matches.
Real Madrid's match against Athletic Bilbao is indeed a match that is quite difficult to predict because Athletic Bilbao is also in good form, but no matter how strong Bilbao is, I don't think it will be able to exceed Real Madrid's very strong performance this season, both of them certainly don't want to lose any points. The points they collect are very significant, a draw is possible and that could be a fair result for both clubs to increase their total points and maintain their respective positions.