Paris Saint-Germain took a big step towards reaching the Champions League final as Ousmane Dembélé's early goal sealed a 1-0 win at Arsenal in a tense first leg of the semifinal on Tuesday. Dembélé fired home off the post in the fourth minute as PSG dominated the opening stages and Luis Enrique's side held firm to take a precious advantage back to the French capital. Arsenal, playing in the semifinal for the first time since 2009, improved after a lacklustre start and had a Mikel Merino goal ruled out after the break while PSG keeper Gianluigi Donnarumma made several fine saves. PSG should have given themselves a bigger cushion for the second leg but Bradley Barcola and Gonçalo Ramos both squandered gilt-edged chances late on. The second leg takes place in Paris next Wednesday with the winners facing either Inter Milan or Barcelona in Munich.