London (AFP) - Aaron Ramsey spared Arsenal's blushes as the Wales midfielder's stoppage-time strike finally saw off 10-man Crystal Palace in a dramatic 2-1 victory on Saturday.
Arsene Wenger's side believe they are capable of winning the Premier League for the first time since 2004 after ending a nine-year trophy drought with their FA Cup triumph last season.
But the Gunners were in danger of making a slow start to their title challenge after falling behind to Brede Hangeland's first-half opener at the Emirates Stadium.
Laurent Koscielny equalised before the break, but the managerless visitors, who saw boss Tony Pulis leave on the eve of the season due to a row over transfer policy, were able to keep Arsenal at bay for long periods.
The turning point came when Palace midfielder Jason Puncheon was dismissed for two yellow cards near the end and Ramsey, who scored 18 goals last season including a winner in the FA Cup final, was in the right place at the right time to force home another vital goal in the first minute of stoppage time.
Having seen his side rout Premier League champions Manchester City 3-0 to lift the Community Shield last week, Wenger had decided to name an unchanged line-up.
The Sanogo call was an interesting one considering he contributed no goals to the Arsenal cause last season, while Giroud weighed in with 22.
Palace had bigger concerns after Pulis's shock decision to walk out following a dispute with the board over signings.
The former Stoke manager had been frustrated to have been handed just Hangeland, Fraizer Campbell and Martin Kelly. All three were given debuts by caretaker manager Keith Millen and the Palace new-boys were instrumental in their team's stubborn display.
Sanchez made an instant impact on the right and his skills helped Jack Wilshere find Ramsey in the penalty area.
The Wales midfielder went down under Scott Dann's challenge but play continued.
Sanogo was making little headway but Sanchez was full of confidence and the Chile winger tried his luck from distance with a chip that drifted just wide.
Palace were content to defend in numbers and Campbell cut an isolated figure up front.
Sanogo poked a shot poorly wide before Wilshere tested Julian Speroni in the Palace goal for the first time with a low drive diverted round a post for a corner.
Palace's response was to take a 35th-minute lead through former Fulham centre-back Hangeland, who came charging through to head home Puncheon's corner.
Arsenal's marking had been poor but they were level just before the break when French defender Koscielny escaped Hangeland and stayed on-side by a fraction to head in Sanchez's free-kick.
Arsenal made two changes early in the second half, with Nacho Monreal replacing Kieran Gibbs at left-back and Giroud coming on for Sanogo, to the home fans' approval.
A third switch soon followed when Wilshere, hurt by Marouane Chamakh, was replaced by Alex Oxlade-Chamberlain.
Kelly was booked for a foul on Sanchez as Palace defended by any means possible, with Puncheon picking up a second yellow in the final minute.
The 10 men were seconds away from escaping with a point, but they were undone when Giroud won a header at the back post and Debuchy swivelled to fired in a shot that Speroni could only parry to Ramsey, who gratefully fired home the rebound from almost on the line.