Mikel Arteta’s side arrived in the north-east with three league victories from three matches and left with another three points, but the scoreline did not tell the full story. Sunderland created several opportunities and had a major chance to equalise after being awarded a second-half penalty.
Arsenal were forced to defend for long periods as Sunderland pressed with intensity, while David Raya once again demonstrated his importance between the posts.
The first half ended goalless, with neither side able to establish a decisive advantage. Arsenal struggled to find their usual rhythm, while Sunderland remained disciplined and dangerous on the counter.
Arteta responded at half-time with changes, bringing on Bruno Guimaraes and Jurrien Timber as Arsenal looked to gain greater control of the match.
The changes eventually paid off.
In the 58th minute, Guimaraes broke the deadlock, receiving the ball from Declan Rice before producing an excellent finish into the top corner to put Arsenal 1-0 ahead.
The goal came shortly after a pivotal moment at the other end.
Sunderland were awarded a penalty, with Enzo Le Fee stepping up to take responsibility. However, David Raya produced a crucial save to deny the Sunderland midfielder and preserve Arsenal’s lead.
Raya's intervention proved decisive as Sunderland continued to search for an equaliser.
The hosts pushed forward in the closing stages and came close on several occasions, but Arsenal's defensive organisation held firm.
Sunderland's hopes finally disappeared deep into stoppage time. Reinildo Mandava was sent off after receiving a second yellow card, having fouled Saka inside the penalty area.
Bukayo Saka converted the resulting penalty in the seventh minute of added time, sealing a 2-0 victory for Arsenal.
Match result
• Sunderland: No goals
• Arsenal: Bruno Guimaraes 58', Bukayo Saka 90+7' (pen)
The victory means Arsenal have now won all four of their Premier League matches this season, giving them a perfect 12-point start and keeping them at the top of the table.
The result was particularly impressive given the circumstances. Arsenal had travelled to Sunderland only days after their Champions League victory over Napoli and were forced to dig deep against an energetic home side.
Raya's penalty save proved to be the turning point, while Guimaraes' introduction provided Arsenal with the attacking spark they had lacked during the opening 45 minutes.
For Guimaraes, the goal was also a significant personal moment. The Brazilian midfielder, who arrived at Arsenal after his Newcastle United spell, responded to the hostile reception from the home crowd with a superb long-range finish.
Sunderland can take encouragement from their performance despite the defeat. Régis Le Bris' side competed strongly against the reigning champions and had opportunities to make the result considerably closer.
Arsenal, however, demonstrated the resilience required of a side chasing another Premier League title. Four matches into the campaign, Arteta's team remain perfect in the league and have conceded just one goal.
The Gunners will now prepare for their next Premier League fixture against Brighton, while their early-season title defence continues to gather momentum.