With victory assured, Brady smirked. It was most certainly not a smile, nor was it a grin. Call it a knowing snicker.

• Once again, it was the underdog Giants across the field who were leading the game, and on his sideline Tom Brady could not help but vehemently bang his helmet on the bench in enduring frustration. Since Brady had seen this turn of events more than once before, he had safely removed his head from the helmet first.

  That was in the first half of the Tampa Bay Buccaneers’ visit to MetLife Stadium in East Rutherford, N.J., on Monday night. About 90 minutes later, in the contest’s closing seconds, with the Buccaneers clinging to a slim lead, Brady returned to the team bench as the Giants ran a play near the Tampa Bay goal line that could send the game into overtime.

  Still and motionless, Brady awaited the result with the grimmest of expressions.

  But Eli Manning is no longer a Giant, and Brady traded in his New England Patriots jersey in March. The Giants, defeated in 17 of their last 20 games, fell just short again, losing, 25-23.

  With victory assured, Brady smirked. It was most certainly not a smile, nor was it a grin. Call it a knowing snicker, but at that moment, it felt as if Brady was more than simply relieved to again exorcise an old demon in the Giants, against whom he has three consecutive victories since the bitter Super Bowl defeat after the 2011 regular season.

  Yes, any opportunity to add to the woes of the reeling Giants was a bonus, but Brady could be forgiven if he was sensing the accomplishment, and great timing, of his daring career shift eight months ago. Not only are the Brady-inspired Buccaneers (6-2) one of the best teams in the league, the Patriots (2-5) may be staggering toward a complete overhaul with Coach Bill Belichick — of all people — even conceding his team is undermanned.

  As Brady was warming up on the field before Monday’s game, the N.F.L. was newly absorbing comments from Belichick, who said his team’s lack of depth this year was a result of the Patriots’ abundant spending in recent seasons, which left them with little room to pursue players in the 2020 off-season.

  “It’s obvious we didn’t have any money,” Belichick told the Boston sports talk radio station WEEI on Monday. “It’s nobody’s fault. I mean, it’s what we did the last five years. We sold out and won three Super Bowls, played in a fourth and played in the A.F.C. championship game. This year, we had less to work with. It’s not an excuse, it’s just a fact.”

  In the wake of the Patriots’ troubles so swiftly after Brady’s exit from New England, all manner of comparisons are in vogue. Most obvious, Brady’s six victories in Tampa Bay and the two earned by his Patriots successor, Cam Newton, who has six interceptions and one lost fumble in his last four games. Brady has one interception and has not lost a fumble in his last six games.

  More popular when it comes to fun facts in the aftermath of Brady’s departure from his football home for the previous 20 seasons is his record as a regular-season starter in New England and Tampa Bay, 225-66. Belichick’s record as a head coach without Brady as his starting quarterback with the Patriots and when he was head coach in Cleveland: 56-68.