Inigo Perez’s reign as Rayo's new manager got off to the worst possible start as Los Franjirrojos conceded within just three minutes.
A rapid Real Madrid counterattack did the damage, culminating in Joselu converting Federico Valverde’s low cross with a precise first-time finish.
Los Blancos had the bit between their teeth, continuing to cause havoc down the right flank. Joselu looked to have headed in his and Real’s second soon afterwards, but the strike was chalked off as the ball went out of play during the build-up.
Despite starting on the back foot, Perez’s side eventually came out of their shell and were rewarded for a more positive approach when Oscar Trejo’s volley struck Eduardo Camavinga’s hand in the penalty area.
Referee Alejandro Muniz Ruiz pointed to the spot following a swift VAR review, and De Tomas held his nerve, curling his first LaLiga goal of the campaign into the bottom corner past a full-stretch Andriy Lunin.
An open first half gave way to a more cagey opening to the second period, yet Los Blancos increasingly looked more dangerous as the half edged on.
Brahim Diaz’s piercing through ball released Joselu in the area, whose resulting shot was gathered by Stole Dimitrievski.
Carlo Ancelotti turned to his bench for inspiration in the final 15 minutes, and Toni Kroos almost made an instant impact, whipping a 25-yard free-kick towards the bottom corner that had Dimitrievski scrambling across the goalmouth to divert to safety.
To sum up a disappointing afternoon for the visitors, Daniel Carvajal received a second booking in injury time and was sent off for lashing out at Kike Perez.
After losing three matches in a row and sacking former manager Francisco, Rayo desperately needed a positive performance against city rivals Real, and Los Franjirrojos certainly delivered as they held onto a draw to move eight points clear of the relegation zone.
With six first-team players on the treatment table, including talisman Jude Bellingham, the visitors looked fatigued after three matches within eight days and dropped points here could open the door for chasing Girona to close the gap on Los Blancos at the top of LaLiga.
Flashscore Man of the Match: Raul de Tomas (Rayo Vallecano)
