The San Jose Sharks’ top priority if they want to continue challenging for a playoff spot down the stretch is keeping the puck out of their net.

In that regard, the Sharks’ game Tuesday night was pretty much a disaster. They allowed two goals in the opening 5:39 of the first period, two more in the second period, and an especially deflating one early in the third in a 6-3 loss to the red-hot Buffalo Sabres at KeyBank Center.

Macklin Celebrini, Kiefer Sherwood and Alex Wennberg all scored for the Sharks, with Sherwood’s goal at the 19:29 mark of the second period cutting the Sabres’ lead to 4-2, giving San Jose some life.

But the Sharks, caught running around in their own zone, allowed a second goal to Jack Quinn 33 seconds into the third period and never fully recovered in their third straight loss.

“They’re obviously playing with a lot of confidence and belief in how they need to play. We saw that real quickly there in the first period,” Sharks coach Ryan Warsofsky said of the Sabres. “We had some moments where we thought we could kind of get out of the hole, and next thing you know, we shoot ourselves in the foot again.”

Quinn completed the hat trick, the first of his NHL career, with an empty-net goal with 2:46 to play as the Sabres (40-19-6) won their eighth straight game, as the Sharks (30-26-6) opened a critical five-game road trip on a sour note.

Buffalo is now 22-4-1 at home against San Jose all-time.

“We kind of hurt ourselves a little bit,” Wennberg said. “Turnovers, decision making. Obviously, not the game we talked about to have a great start to this road trip, I feel like we let ourselves down.”

Goalie Yaroslav Askarov had 20 saves for the Sharks, who, for the moment, remained one point back of the Seattle Kraken for the second and final wild card spot in the Western Conference. The Kraken hosted the Nashville Predators late Tuesday night.

Celebrini’s goal, his 33rd of the season, gave him 90 points on the season, and Sherwood set a new career-high with his 20th goal of the year. With 90 points in 62 games, Celebrini became the third-fastest teenager to score 90 points in a season, trailing only Sidney Crosby (54 games in 2006-07) and Wayne Gretzky (56 games in 1979-80).

It wasn’t nearly enough.

The Sharks gave up an odd-man rush on Quinn’s first goal to open the scoring in the first period, and allowed net-front goals to Alex Tuch and Jason Zucker in the first and second periods, respectively. A Sam Dickinson puck-handling miscue also led to a Beck Malenstyn goal early in the second period.

The Sharks now have a goal differential of -26 on the season, and were 29th in the NHL in goals allowed per game (3.46) before Tuesday. The Sabres are the fifth-highest scoring team in the NHL at 3.51 goals per game.

“A team with their offensive capabilities, if you’re not defending hard, they’re going to expose you,” Sharks winger Barclay Goodrow said. “If you’re not taking care of the puck, playing smart hockey, then it looks like how it did tonight.”

The Sharks trailed 2-1 after an entertaining first period that also featured two fights and a highlight-reel play from the Sharks’ top line.

The Sharks allowed goals to Quinn and Tuch and trailed 2-0 after the opening 5:39, but started to find their game as the period went on.

William Eklund and Shakir Mukhamadullin each had quality scoring chances before a Celebrini forecheck caused Tuch’s errant pass inside the Buffalo zone. Will Smith pounced on the loose puck and fed Celebrini, who won the race to the front of the net and beat Sabres goalie Alex Lyon.

Zack Ostapchuk fought Logan Stanley with 4:26 left in the first period, and Goodrow, responding to a hit on Celebrini, fought Malenstyn just 22 seconds later.

Only four players have scored at least 90 points in one season for the Sharks. Joe Thornton had 114 in 2006-07, 96 in 2007-08, and 92 in 2005-06 when he joined the Sharks in November of that season. Jonathan Cheechoo had 93 points that year, and Erik Karlsson had 101 points in 2002-23 in his third Norris Trophy season.

This road trip is arguably the Sharks’ most challenging of the season, as every team they play, as of Tuesday, was either in a playoff spot or just outside one.

It’s easily the most important. With a trip of .500 or better, the Sharks would put themselves in an ideal spot for the stretch run, with only four of their final 16 games coming against teams that are now in a playoff position.

A losing record on the trip, which continues with stops in Boston, Montreal, Ottawa, and Edmonton, and the Sharks risk losing ground in a tight Western Conference playoff race while adding more importance to their remaining games.

NOTABLE

The Sharks made one lineup change from Saturday’s loss, re-inserting forward Philipp Kurashev into the lineup with scratching Ryan Reaves. Kurashev was a surprise scratch against the Islanders, but started Tuesday’s game on a line with Alex Wennberg and Kiefer Sherwood.