Tuncay Sanli blasted a huge hole in Liverpool's Barclays Premier League title challenge as Middlesbrough gave their survival hopes a massive boost.
The Turkey international struck for the second time in four days after Xabi Alonso's own goal had given the Teessiders an unlikely half-time lead.
It was Boro's first league victory and the Reds' first league defeat in 15 attempts, and was hugely significant to both clubs for starkly contrasting reasons.
The hosts last won at Aston Villa on November 9 and had not collected all three points at the Riverside Stadium since 11 days earlier, and Alonso's goal was their first in the league for 526 minutes.
However, Gareth Southgate's men were well worth a win which gives them genuine hope of escaping the drop, but leaves Liverpool's title hopes in shreds with leaders Manchester United seven points clear with a game in hand.
Liverpool arrived on Teesside with talk of manager Rafael Benitez's unsigned contract and the impending departure of chief executive Rick Parry dominating the headlines.
However, the only focus at the end of a week which brought the club a famous Champions League victory over Real Madrid at the Bernabeu Stadium was the league title which has eluded them since 1990.
Even after Boro's creditable performance in beating West Ham on Wednesday evening to book their place in the FA Cup quarter-finals, few in a crowd of 33,724 - the biggest of the season at the Riverside - were expecting a home win.
Indeed, for the opening half-hour, there seemed only one likely winner despite Gary O'Neil forcing a good reaction save from Jose Reina from Stewart Downing's 11th-minute cross.
Opposite number Brad Jones had already kept out close-range efforts from Nabil El Zhar and Dirk Kuyt as the visitors piled on the pressure, although even the craft of returning skipper Steven Gerrard, making his 300th start for the club, and Alonso could not break the Teessiders down on a consistent basis.
But when the opening goal finally arrived, it came at the other end, and ended an agonising wait for the home side.
Not since Afonso Alves' 45th-minute strike in the 1-1 derby draw with Sunderland on January 10 had Boro found the back of the net in a league game, and they needed a helping hand to end the drought.
Alonso instinctively stuck stuck out a leg as Downing's 31st-minute corner sped across the six-yard box, but only succeeded in diverting the ball past the helpless Reina.
The goal seemed to galvanise the home side, who might have extended their lead four minutes before the break when Downing robbed full-back Martin Skrtel and forced Reina into a good save.
However, Southgate's men returned expecting an onslaught and knowing there was a long way to go before they could even contemplate all three points.
Liverpool should really have been back on level terms within three minutes of the restart when Gerrard ghosted into the box and pulled the ball back invitingly for El Zhar.
However, the youngster hammered his shot high over the bar to let Boro off the hook.
Jeremie Aliadiere might have increased the visitors' woes three minutes later when he was picked out by O'Neil inside the box, but he was similarly inaccurate.
Benitez's side continued to dominate possession, but they were struggling to do anything meaningful with it as Boro's stubborn defence proved more than adequate to keep them at bay.
The game's second goal came with 63 minutes gone, and again it was the visitors who found themselves on the wrong end of it.
O'Neil slid the ball into the path of Aliadiere down the right and when he squared for Tuncay, the Turkey international guided his shot past Reina into the bottom corner to send the home crowd into raptures.
Jones saved from Gerrard and Kuyt failed to connect with his skipper's cross with the goal at his mercy as the game slipped further from Liverpool's grasp, and things might have been even worse with 18 minutes remaining.
Downing and Tuncay combined to open up the Reds once again and present Marlon King with a glorious opportunity, but Reina came to the rescue with a two-handed save.
In truth, the visitors never looked like pulling off a rescue mission as Boro coasted to a fine win.
The Turkey international struck for the second time in four days after Xabi Alonso's own goal had given the Teessiders an unlikely half-time lead.
It was Boro's first league victory and the Reds' first league defeat in 15 attempts, and was hugely significant to both clubs for starkly contrasting reasons.
The hosts last won at Aston Villa on November 9 and had not collected all three points at the Riverside Stadium since 11 days earlier, and Alonso's goal was their first in the league for 526 minutes.
However, Gareth Southgate's men were well worth a win which gives them genuine hope of escaping the drop, but leaves Liverpool's title hopes in shreds with leaders Manchester United seven points clear with a game in hand.
Liverpool arrived on Teesside with talk of manager Rafael Benitez's unsigned contract and the impending departure of chief executive Rick Parry dominating the headlines.
However, the only focus at the end of a week which brought the club a famous Champions League victory over Real Madrid at the Bernabeu Stadium was the league title which has eluded them since 1990.
Even after Boro's creditable performance in beating West Ham on Wednesday evening to book their place in the FA Cup quarter-finals, few in a crowd of 33,724 - the biggest of the season at the Riverside - were expecting a home win.
Indeed, for the opening half-hour, there seemed only one likely winner despite Gary O'Neil forcing a good reaction save from Jose Reina from Stewart Downing's 11th-minute cross.
Opposite number Brad Jones had already kept out close-range efforts from Nabil El Zhar and Dirk Kuyt as the visitors piled on the pressure, although even the craft of returning skipper Steven Gerrard, making his 300th start for the club, and Alonso could not break the Teessiders down on a consistent basis.
But when the opening goal finally arrived, it came at the other end, and ended an agonising wait for the home side.
Not since Afonso Alves' 45th-minute strike in the 1-1 derby draw with Sunderland on January 10 had Boro found the back of the net in a league game, and they needed a helping hand to end the drought.
Alonso instinctively stuck stuck out a leg as Downing's 31st-minute corner sped across the six-yard box, but only succeeded in diverting the ball past the helpless Reina.
The goal seemed to galvanise the home side, who might have extended their lead four minutes before the break when Downing robbed full-back Martin Skrtel and forced Reina into a good save.
However, Southgate's men returned expecting an onslaught and knowing there was a long way to go before they could even contemplate all three points.
Liverpool should really have been back on level terms within three minutes of the restart when Gerrard ghosted into the box and pulled the ball back invitingly for El Zhar.
However, the youngster hammered his shot high over the bar to let Boro off the hook.
Jeremie Aliadiere might have increased the visitors' woes three minutes later when he was picked out by O'Neil inside the box, but he was similarly inaccurate.
Benitez's side continued to dominate possession, but they were struggling to do anything meaningful with it as Boro's stubborn defence proved more than adequate to keep them at bay.
The game's second goal came with 63 minutes gone, and again it was the visitors who found themselves on the wrong end of it.
O'Neil slid the ball into the path of Aliadiere down the right and when he squared for Tuncay, the Turkey international guided his shot past Reina into the bottom corner to send the home crowd into raptures.
Jones saved from Gerrard and Kuyt failed to connect with his skipper's cross with the goal at his mercy as the game slipped further from Liverpool's grasp, and things might have been even worse with 18 minutes remaining.
Downing and Tuncay combined to open up the Reds once again and present Marlon King with a glorious opportunity, but Reina came to the rescue with a two-handed save.
In truth, the visitors never looked like pulling off a rescue mission as Boro coasted to a fine win.