Arsenal were handed their first defeat of the season at Bournemouth, but it could have been a very different result. William Saliba’s first-half red card meant that Arsenal were on the back foot for most of the game, but at 0-0, they had a big chance to take the lead. Substitute Gabriel Martinelli came on for the disappointing Leandro Trossard, but the Brazilian could not continue his fine form which saw him score in his last two Premier League games. Martinelli had a huge chance to take the lead after Mikel Merino played him in, following a mistake from Kepa Arrizabalaga. However, the winger …