Kai Havertz scored a stoppage-time goal assisted by Gabriel Martinelli to give Arsenal a 1-0 victory over Sporting CP in the Champions League quarter-final first leg.Goalkeeper David Raya made five crucial saves to maintain a clean sheet while Mikel Arteta praised the pragmatic performance following recent domestic cup losses.The Premier League leaders take a narrow advantage back to London for the second leg as they seek their first title in the prestigious European tournament.