Harry Kane found the net for the second time in two Premier League games as Tottenham Hotspur beat Sunderland 1-0 on Sunday, but was stretchered off late on.
The home side claimed all three points thanks to Kane's close-range finish after 59 minutes following a mistake by Sunderland centre-back Papy Djilobodji.
As a result, Spurs went above rivals Arsenal in the table after not losing any of their first five league games of the season for the first time in 12 years, while Sunderland - who saw Adnan Januzaj sent off at the death - remain in the relegation zone as they still seek their first top-flight win this campaign.
However, Mauricio Pochettino's afternoon turned sour when Kane was carried off three minutes from time with a serious-looking ankle injury, with the Argentine later revealing his striker was set to undergo a scan to determine the extent of the problem.
The Tottenham boss made three changes from the side that lost 2-1 to Monaco in the Champions League at Wembley in midweek, with Mousa Dembele making his first Premier League appearance of the season after completing a domestic suspension.
Meanwhile, Moussa Sissoko made his first start for the club since joining from Newcastle in the summer and there was a reshuffle in defence, with Eric Dier dropping back to play in the heart of the back line and Jan Vertonghen filling in at left back for the injured Danny Rose.
As for the visitors, David Moyes also made three alterations from the team that lost 3-0 at home to Everton in their last Premier League game, all in midfield, with the Scot recalling captain Lee Cattermole, Didier Ndong and Steven Pienaar.
However, Sunderland made an unexpected late change, with Jason Denayer coming in for Patrick Van Aanholt moments before kick-off, and the Belgium international was given a tough examination by Son Heung-min on his Premier League debut for the club.
The South Korea international was a bundle of energy down the left flank in the opening exchanges, with Sunderland goalkeeper Jordan Pickford being forced into a brilliant reaction save at his near post to keep out Kane's close-range shot after nine minutes.
Pickford was an increasingly busy figure as the first period wore on as shots rained down on the visitors' 'keeper, with one particular effort from Son Heung-min six minutes before half-time beating the England U21 international, only to strike the outside of the post.
However, despite all Spurs' pressure, it was Sunderland who created the best chance of the first half after good play by Januzaj in the box saw the Belgian escape to the right-hand byline and pull the ball back for Steven Pienaar, whose close-range effort was cleared off the line by Kyle Walker.
The pattern of the second half was much the same as the first, with Spurs pressing for the opening goal, which finally came just before the hour-mark, although Sunderland will be disappointed with their part in it.
Kyle Walker swung in a cross from the right which Dele Alli headed back across goal, only for Djilobodji to make a hash of his clearance in the six-yard box and present Kane with a simple tap-in at the far post.
The home side - who had a Premier League record so far this season of 31 shots on goal - had several chances to increase their lead in the final quarter of the game, with Pickford furthering his already growing reputation by denying Alli and substitute Erik Lamela with excellent stops, while Dier also flashed a shot inches past the far post.
However, Pochettino may now have to make do without the likes of Kane, Dier, who suffered a hamstring injury, and Walker, who also appeared to be nursing a hamstring problem in the closing stages, over the course of the next few weeks.
As for the Black Cats, Moyes saw on-loan Manchester United wide man Januzaj dismissed in the 90th minute having picked up two bookings in the final nine minutes of the game, the first a needless caution for dissent.
Player ratings
Tottenham: Lloris (6), Walker (6), Alderweireld (7), Dier (7), Vertonghen (6), Dembele (8), Wanyama (7), Sissoko (7), Alli (7), Son (9), Kane (7)
Subs used: Janssen (6), Lamela (7), Davies (6)
Sunderland: Pickford (8), Manquillo (6), Kone (6), Djilobodji (6), Denayer (5) Januzaj (7), Kirchhoff (7), Cattermole (6), Ndong (6), Pienaar (5), Defoe (7)
Subs used: Khazri (6), Watmore (7), McNair (6)
Man of the match: Son Heung-min