Last night's damaging defeat makes it more probable that when Bryan Robson's side arrive at Wembley for the FA Cup final they will have taken their leave of the Premiership.
Andy Sinton's late goal at White Hart Lane means Middlesbrough remain five points short of safety. Not only is time running out, it is their most difficult opponent between now and the end of the season: their final four games - three of which are away - come in the space of nine days.
Of course, a congested fixture programme is nothing new for these tired, brave men of Teesside. This match followed just a day's grace after they had won their replayed FA Cup semi-final against Chesterfield and despite the efforts they put in here it seemed inevitable that the fresher legs of Tottenham would ultimately prevail.
"It was ridiculous asking us to play two days after that game," Robson said afterwards. "It definitely affected us, that little bit of spark had drained away."
With minutes remaining, the Boro substitute, Craig Hignett, might still have rescued them a point when the tireless Juninho played him in. This time Ian Walker, who had made three crucial saves, was not called upon as the ball dropped on to the roof of the net. Visiting heads dropped with it and will not be lifted for some time.
Not since Brighton in 1983 has a side won through to the FA Cup final and suffered the indignity of relegation. When Boro strung together four successive wins in early spring, it looked as if that particularly statistic would not be relevant, but since then not only did they lose their appeal against the three points lost because of the Blackburn no-show but also they have failed to win in the League.
The cups have got in the way but if they were to fall on 11 May, would it really be that poor a season? FA Cup finals do not come around all that often and Wembley next month will stage Middlesbrough's first in 121 years as a football club.
Their unease when facing balls hit high and long by Tottenham was apparent early on. Ben Roberts flapped at one in his penalty area, Sol Campbell thundered a header against the crossbar, and the portents were against Robson's men.
Then Juninho, drawing on extra reserves of energy from God knows where, took over and Middlesbrough stock rose. The little Brazilian curled one towards the top-right corner, but up reached Walker's hand. Next, the goalkeeper dived to keep out Emerson's firm header. Spurs then seized the next chance that came along. Teddy Sheringham's aerial power was always a threat and when he headed on Justin Edinburgh's deep, angled cross there was Sinton, on his 600th League and cup appearance, to bundle the ball in at the far post.
Tottenham Hotspur (5-3-2): Walker; Austin, Vega, Calderwood, Campbell, Edinburgh; Dozzell, Howells, Nielsen; Sheringham, Sinton. Substitutes not used: McVeigh, Fenn, Hill, Brady, Bardsen (gk)
Middlesbrough (4-4-2): Roberts; Blackmore, Pearson, Vickers, Kinder; Stamp (Hignett, 82), Emerson, Mustoe, Juninho; Ravanelli (Freestone, 82), Beck. Substitutes not used: Whyte, Whelan, Schwarzer (gk).
Referee: P Durkin (Dorset).