Tottenham’s resurgence under Juande Ramos continued, almost inevitably, at bottom-of-the-table Derby, whose resilience crumbled in the second half when Dimitar Berbatov and Jamie O’Hara were introduced off the bench. They changed the tempo and provided class and a cutting edge to compensate for what the Tottenham manager called the “hurry-scurry of the first half”.

Derby capitulated, unable to maintain their prodigious workrate. “We needed somebody to put his foot on the ball and control the game and O’Hara did that well, bringing a bit more order to our play,” said Ramos. “We have lots of big games coming up, so the idea is not to rotate players but give some of them a rest and today was Berbatov’s turn. With the match at 0-0, we wanted three important points and he came on and played his part in the team’s magnificent effort.”

The Bulgarian provided a natural focal point for Tottenham’s attack when he made his entrance. He held up the ball and equipped his team instantly with the threat they had lacked throughout the first half, and heart and endeavour could not compensate for Derby’s inadequacies at the back when Spurs showed their ruthlessness.

Tottenham were bright, dynamic and quick on the counter-attack. When Derby’s Craig Fagan crossed hopefully into the visitors’ penalty area, Jermaine Jenas intercepted and Darren Bent accelerated into the penalty area to create a shooting opportunity. He struck his effort low and hard but Roy Carroll dived to his left to save. With the same chance, Berbatov would doubtless have done better.

Robbie Keane was presented with another chance when Alan Hutton’s pass from the right across the box came to the Irishman, whose sharp turn was followed by a right-footed shot that Carroll did well to push away.

Derby lost Darren Moore through injury and, within minutes, Tottenham’s Michael Daw-son limped off with a suspected muscle tear in his left leg, which is likely to keep him out of the Carling Cup final. “It’s the early stages but it’s a muscle injury and he could be out for two to three weeks,” Ramos speculated.

Spurs showed vulnerability immediately and with Dawson’s replacement, Younes Kaboul, not yet on the pitch, Stephen Pearson charged through the middle and passed to Emanuel Villa, whose shot was well saved by Radek Cerny.

The Rams had a genuine creative resource in Pearson, who drove forward through the Spurs midfield again and released Giles Barnes. With only Cerny to beat, he panicked and failed to hit the target.

Aaron Lennon’s pace created an opening when he pulled the ball back from the byline and Kaboul’s close-range shot forced a good reflex save out of Carroll.

The Rams remained positive into the second half and a clever one-two on the edge of the penalty area between Kenny Miller and Barnes yielded a chance for the Scotland striker to shoot before Kaboul deflected his shot.

A free kick by Robbie Savage was cleared only to Fagan but the midfielder fired his mediocre shot straight at Cerny.

Derby were playing well but they were at their limit while Tottenham had still to play their ace card. Jenas played a one-two with O’Hara before he spread the ball to his right. Hutton picked up possession and advanced into the box before slicing his right-footed shot wide.

Tom Huddlestone did better when a free kick by O’Hara came to him at the far post but his powerful shot was pushed away by Carroll for a corner. O’Hara took the kick and the ball fell to Lennon on the edge of the area but he was profligate, too, firing his half-volley wide.

The pressure was beginning to tell and an error by Savage surrendered possession to Keane, whose quick shot from inside the Derby penalty area beat Carroll but came back off the post.

Finally, Spurs broke the deadlock when Huddlestone played a long ball to Steed Malbranque on the left. He cut inside into the penalty area and his low shot could only be pushed away by Carroll to the feet of Keane, who shot into the empty net for his 19th goal of the season.

Berbatov, introduced 10 minutes earlier, provided the extra dimension and, suddenly, Derby were under siege. Carroll produced two excellent back-to-back saves from Jenas and Berbatov but with nine minutes left a Lennon corner was headed down by Pascal Chimbonda to Kaboul, who sidestepped a defender before dispatching his shot past Carroll. The final ignominy for Derby came when Malbranque’s stoppage-time cross struck Alan Stubbs’s right arm. Berbatov struck the penalty kick into the bottom left corner. “For an hour they looked rattled but they brought on Berbatov and once the first went in they looked a different team – as we did,” said Paul Jewell, the Derby manager.

Match stats

Star man: Dimitar Berbatov (Tottenham)

Player ratings: Derby: Carroll 5, Leacock 6, Moore 4 (Todd 11min, 7), Stubbs 6, Edworthy 6 (Jones 78min), Fagan 7, Barnes 6, Savage 5 (Sterjovski 74min), Pearson 7, Villa 6, Miller 6

Tottenham: Cerny 6, Hutton 7, Dawson 5 (Kaboul 14min, 7), Huddlestone 7, Chimbonda 6, Lennon 6, Jenas 7, Boateng 6 (O’Hara ht, 7), Malbranque 7, Bent 5 (Berbatov 58min, 8), Keane 7

Scorers: Tottenham: Keane 68, Kaboul 81, Berbatov 90 pen

Yellow cards: Derby: Leacock, Miller, Jones, Stubbs. Tottenham: Chimbonda

Referee: M Atkinson

Attendance: 33,058