Oxlade-Chamberlain got a goal in the 88th minute, but his late strike was not enough to get the Reds back in the game.
Afterward, he spoke about the return to match action for Van Dijk and Gomez, who were absent for much of last term.
He told the club website: "It was a nice moment to see them come on – it took my mind off the fact it was red hot and I was blowing! Nice seeing them come on and clapping them on. I'm absolutely delighted for them.
"Obviously I know full well what they've been through – to an extent, everyone's journey is a bit different – but I know how much hard work they've put in and they've been a little tag team helping each other through. So to see them come back at the same time, I'm absolutely delighted. They've been really good in training, looked really sharp.
"Obviously now it's just the fitness and the durability they'll build on. It's a massive, massive asset for us to have them back on the pitch and in and around the team as well because they are both characters that are massive for the team. I was delighted for them."