LONDON (AFP) - Only six Premier League sides were left in the last 16 of this season's FA Cup after Sheffield United beat Manchester City 2-1 at Bramall Lane on Sunday.

The Blades, relegated to the second-tier Championship at the end of last season, were 2-0 up inside 25 minutes through goals from Luton Shelton and Jonathan Stead before City substitute Daniel Sturridge pulled one back early in the second half.

City's defeat left Arsenal, Chelsea, Liverpool, Middlesbrough, Portsmouth and Manchester United - who beat Tottenham 3-1 earlier on Sunday - as the lone representatives from English football's top flight left in the hat for Monday's fifth round draw.

No strangers to misfortune, City went behind in bizarre fashion in the 12th minute with a goal that owed much to the balloons which littered the pitch in front of Joe Hart's goal.

Lee Martin, on loan from Manchester United, delivered a low cross that took a slight deflection off the leg of City captain Richard Dunne.

The ball also clipped a balloon, a deviation that appeared to deceive Michael Ball as he missed his clearance.

It almost confused Shelton too but the Jamaica international kept his composure and beat Hart from six yards to give Sheffield United, managed by former Manchester United captain Bryan Robson, the lead.

Elano then hit the post for City and he was denied again when experienced Blades keeper Paddy Kenny made a superb save to tip a curling free-kick around the post.

But for all City's pressure it was Sheffield United who scored next when Stead seized on a loose ball from 12 yards after City failed to clear a cross from Derek Geary.

However, former England coach Sven-Goran Eriksson's decision to bring on Sturridge after half-time was rewarded when with his first touch of the game, he struck a left-foot volley off the underside of the crossbar.

At Old Trafford, Cristiano Ronaldo took his tally for the season to 25 goals as he scored twice in a come-from-behind victory.

Spurs, who earlier in the week thrashed Arsenal 5-1 to book their place in the League Cup final, had to play the final 21 minutes down to 10 men after defender Michael Dawson was sent-off for deliberate handball in the incident that led to Ronaldo's goal from the penalty spot that made it 2-1.

Ronaldo then netted again two minutes before time in a match where Spurs striker Robbie Keane gave the visitors the lead in the 24th minute.

"It was a fantastic Cup tie," said United manager Sir Alex Ferguson.

"Tottenham had the best chances of the match but they didn't take them. We started well but then we seemed to be too relaxed. We allowed Tottenham a bit of momentum, they scored a fine goal and I think it roused us."

Spurs went ahead when Aaron Lennon moved past Patrice Evra and squared the ball to Keane who scored from close range as United conceded for the first time in five matches.

But the hosts were level before half-time when veteran Wales winger Ryan Giggs shielded the ball from Lee Young-Pyo and so allowed space for Carlos Tevez to shoot beyond Spurs keeper Radek Cerny.

United's second goal came after keeper Edwin van der Sar's long punt downfield saw the ball travel from one box to the other and Dawson, under pressure from Wayne Rooney, was red-carded after pushing the ball away with his hand. Ronaldo scored from the spot after sending Cerny the wrong way.

Tottenham almost had an equaliser when Bulgaria striker Dimitar Berbatov hit the post six minutes from time with van der Sar beaten.

But Ronaldo then sealed victory when a deflected shot squirmed under Cerny's body in the 88th minute.

In Sunday's other fourth round tie Championship Cardiff City won 2-1 away to League Two Hereford.