Alonso and team-mate Lance Stroll had been struggling with the DRS overtaking device all weekend on their new low-drag wing for Baku's long straights.
The problem came up in Friday practice and continued all the way through both qualifying sessions this weekend, and while Alonso reported no problems during Saturday's 17-lap sprint race he wasn't totally convinced the issues is fully resolved for today's grand prix.
"That's the topic this weekend in our team, but it did work. I think in the race I pressed two times and it did open, so I hope everything is fixed," Alonso said.
"One third time I wasn't looking at the mirror, so I'm not sure but I'm sure the team is analysing all the data available and if we have some tweaks to do we have another chance before tomorrow's race.
He added: "I think we cannot be 100% sure [it will work in the race]. We've been through problems every session, so I don't think that the system is still bulletproof into tomorrow's race, but it's the way it is.
"Even with a DRS it seems very difficult to overtake when you're following cars, so maybe it's not the key factor tomorrow. Even if it doesn't work."
Source: Autosport