Sebastian Vettel says he and Charles Leclerc "cannot pull out miracles" after Ferrari failed to score a point on a chastening afternoon in Belgium.
Both drivers missed out on Q3 on Saturday, but they hoped to salvage something from the weekend on Sunday.
The Scuderia's chances were boosted when McLaren's Carlos Sainz, one of the cars due to start ahead of them, was unable to begin the race due to exhaust failure and Leclerc charged up to eighth by the end of the second lap.
But Leclerc ultimately finished a dreadful 14th, one place behind four-time world champion Vettel, with the team's lack of pace combined with issues at a pit stop for the Monegasque.
After being passed by the likes of Kimi Raikkonen – driving an Alfa Romeo fitted with a Ferrari engine – Vettel found it difficult to find positives.
"I tried a lot of things to drive around these problems, but we were not quick enough," the German said.
"We cannot pull out miracles. The package is what it is.
"We need to stay optimistic and see the good things, even if there are not many."
Leclerc added: "It was extremely frustrating, it's been a very difficult weekend for us, and the race was not any easier. It's difficult for us to overtake, even with the DRS, so we need to work on it."
Vettel hopes his Ferrari will not be as slow in the upcoming two races on home soil at Monza and Mugello.
"Hopefully the problems are Spa-specific," he said. "There are a lot of lessons from this weekend and we have two important races coming we need to focus on.
"We need to stay calm, not get frustrated as being frustrated doesn't take you anywhere."
The last time two Ferrari drivers finished a race but did not score a point was at the 2010 British Grand Prix.
Further up the field, Max Verstappen took third place behind race winner Lewis Hamilton and the championship leader's team-mate Valtteri Bottas.
The Dutchman reflected on an uneventful race from his perspective as he remained second in the drivers' standings in between the Mercedes duo.
"It was pretty boring," he said. "Not really interesting, not much to do. I couldn't keep up with them when they started pushing.
"I ran out of tyres at the end so the last eight laps I was just backing it out and saving the front tyres. It was not really enjoyable out there.
"On the medium tyre I didn’t have a lot of grip and on the hard I was initially catching up to Valtteri but they told him to speed up and I couldn't keep up. It was bit lonely!
"We had no tyres left at the end and I was not taking any risks. We just maximised what we could. I was very close to a puncture but we finish P3 and more than that was not possible.
"Maybe it is not the most satisfying P3 but it is still better than nothing."