Liverpool were knocked out of the FA Cup by Championship club Wolves as Tottenham survived a potential giant-killing of their own by twice coming from behind in a 4-3 win over fourth-tier Wycombe Wanderers.
Seven-times FA Cup winners Liverpool lost 2-1 at home to second-tier Wolves as the Merseysiders' season went from bad to worse.
Defeat meant Liverpool, 10 points behind Premier League leaders Chelsea -- their next opponents at Anfield on Tuesday -- had been knocked out of two cup competitions in four days following their 2-0 aggregate loss to Southampton in Wednesday's League Cup semi-final.
Wolves needed less than a minute to go ahead, Richard Stearman scoring for the Midlands side when he headed in a free-kick.
And four minutes before half-time, they doubled their lead when Andreas Weimann finished an excellent counter-attack.
But, having rarely threatened, a much-changed Liverpool pulled a goal back when Divock Origi scored from close range with four minutes left following a corner.
That, however, was good as it got for Liverpool, who have now won just one of their last eight matches in all competitions.
"We were very bad," Liverpool boss Jurgen Klopp told BT Sport. "We started badly and it didn't really get better."
For Wolves, victory gave them a second Premier League scalp in this season's FA Cup after they knocked Stoke City out in the third round and manager Paul Lambert said: "We'll enjoy the ride. We might get dismantled in the next game but the last two (FA Cup) games have been unbelievable."
- 'Heroes' -
Wycombe threatened an even bigger upset as they surged into a 2-0 lead away to eight-times FA Cup winners Spurs thanks to two first-half goals from captain Paul Hayes only for Son Heung-Min, who scored twice, to grab the winning goal seven minutes into stoppage-time.
Hayes fired Wycombe into a 23rd-minute lead against a Spurs side showing nine changes with a fine volley.
And in the 36th minute, Hayes made it 2-0 from the penalty spot after Spurs' Cameron Carter-Vickers brought down Sam Wood.
But Son pulled a goal back on the hour and four minutes later the north London side were level through a Vincent Janssen penalty after he was brought down in the box.
Wycombe, however, regained the lead though Gary Thompson's 83rd-minute header only, with two minutes of normal time left, for England midfielder Alli, on as a substitute, to make it 3-3.
Wycombe were then cruelly denied even a replay when South Korea forward Son scored with a deflected shot seconds before the final whistle.
"In the second half we increased our level and pushed a bit," relieved Spurs manager Mauricio Pochettino told the BBC.
"Full credit to Wycombe they played very well. Congratulations to them because they were heroes."
Wycombe boss Gareth Ainsworth added: "It was an outstanding effort from the boys."
Chelsea kept their double hopes alive with a comfortable 4-0 fourth-round win at home to fellow west London club Brentford.
Wilian gave Chelsea a 14th-minute lead with when he lifted a free-kick over the wall and into the top corner.
Minutes later, Antonio Conte's men were 2-0 up when Pedro scored at the far post following Michy Batshuayi's defence-splitting pass.
Branislav Ivanovic made it 3-0 before Batshuayi's penalty nine minutes from time completed the scoring.
"I am pleased and very happy for the commitment from my team," Conte told Bein Sports. "It was important to go to the next round and to think about the next game at Liverpool - a tough game."
Manchester City won an all-Premier League tie against Crystal Palace, last season's losing FA Cup finalists, 3-0 courtesy of goals from Raheem Sterling, Leroy Sane and Yaya Toure.
Saturday's late kick-off Cup tie sees top-flight duo Southampton and Arsenal meet at St Mary's.
In other Cup ties, Premier League Burnley beat second-tier Bristol City 2-0, non-league Lincoln stunned Championship leaders Brighton 3-1 and third-tier Oxford upset Championship club Newcastle 3-0.
Blackburn defeated local rivals Blackpool 2-0, Middlesbrough edged out Accrington 1-0 and Huddersfield thrashed Rochdale 4-0
FA Cup holders Manchester United travel to Wigan for a fourth-round tie on Sunday when top-flight sides Watford and Hull are away to Millwall and Fulham respectively.
Non-league Sutton face Championship club Leeds.