"There are some things that have to do with the organisation of the team but other things they have to do with individual skills, individual ability," Mourinho said, when asked about his defenders' lapses. "It's as simple as that."
His implication was clear: Fulham's equaliser had nothing to do with Tottenham's set-up and everything to do with the quality of Sanchez and Dier.
The stalemate, which made it one win in six League matches for Mourinho, will only add to the manager's long-held belief that Spurs are being undone by individual mistakes.
In defence of this argument, Cavaleiro's goal, which cancelled out Harry Kane's header, was only the fourth time Spurs have conceded from open play in this season's Premier League and, in a separate interview with broadcasters, Mourinho was more direct about his side's common failings.
"Once more we concede a goal that is completely avoidable," he said. "Again, we lose a man in the box, which is something that happens the majority of the time in set-pieces. This time it was in free play."
Mourinho was desperate for a new centre-half in the summer and pushed chairman Daniel Levy to sign Milan Skriniar from Inter Milan. The Slovakian was ultimately out of reach and Spurs instead turned to the more affordable Joe Rodon.
In Rodon's only Premier League start to date, he made two errors leading to chances in the 0-0 draw at Chelsea and Mourinho has since stuck with the experience of Toby Alderweireld and Dier, with Sanchez occasionally coming in against quicker attacks.
Alderweireld and Dier are a steady pair, who have helped Spurs' establish the second-best defence in the top flight, but they are certainly no Terry and Carvalho, Ramos and Varane.
Mourinho's preferred approach is based on the belief that one goal should always be enough to win any game, but it is clear he cannot rely on his current crop to execute a philosophy built on such fine margins, which begs the question of why his side continue to sit back after taking the lead.
Last night's derby, which had assumed the proportions of a grudge match given forthright claims from Mourinho and Fulham boss Scott Parker over the rescheduling of the fixture, followed the same pattern as Tottenham's frustrating 1-1 draws at Crystal Palace and Wolves last month.
Mourinho's Spurs remain a work in a progress, but there is little chance of signing a top defender this month, with the club more focused on outgoings.
Until the summer, or until he has more confidence in his current crop of defenders, Mourinho's reluctance to release the shackles and play a more progressive game on the front foot will surely continue to cost Tottenham.
Pragmatism in this context does not necessarily mean safe football; it means doing whatever is necessary to win — and putting the onus on Harry Kane, Heung-min Son and a varied support cast for goals feels a safer bet than continuing to rely on Dier, Sanchez & Co. to keep clean sheets.
In fairness to Mourinho, Spurs had more than enough chances to win but were wasteful in the final third, further highlighting another of their familiar failings: an over-reliance on Kane and Son for goals.
Kane's broke the deadlock with a textbook flying header from Sergio Reguilon's superb cross but Son had an off-day, striking the post moments before Cavaleiro's equaliser.
A well-drilled Fulham side, who displayed no ill-effects from the outbreak of coronavirus which had decimated Parker's squad, looked the more likely winners, with Hugo Lloris saving from the excellent Ruben Loftus-Cheek after Spurs' defence was opened up again.
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