Reference: al-Haawee min Fataawa ash-Shaykh al-Albaanee – Page 187
Question: If one remembers that he has not prayed the ‘Asr [prayer] until after he has prayed the Maghrib [prayer], should he pray the ‘Asr and [redo the] Maghrib [prayers – one right after the other] or the ‘Asr [prayer] only?
Response: He should pray the ‘Asr prayer only, because the Maghrib [prayer] has already been prayed in its [appointed] time, and likewise he [would have] prayed the ‘Asr [prayer] in its [appointed] time because its [appointed] time is when he remembered [he had not prayed] it.
صلى المغرب ثم تذكر أنه لم يصل العصر
المرجع: الحاوى من فتاوى الشيخ الألباني – ص187
السؤال: إذا مُصلِ تذكر أنه لم يُصلِ العصر إلا بعد أن صلى المغرب، هل يصلى العصر و المغرب أو العصر فقط؟
الجواب: يصلى صلاة العصر فقط لأن المغرب صليت في وقتها و كذلك صلى العصر في وقتها لأن وقتها وقت ذكرها.