LONDON — Eberechi Eze’s wonder goal earned Arsenal a crucial 1–0 victory over Newcastle United on Saturday evening with a set of three points which came with two caveats. The two players who combined for the game’s only goal both hobbled off the pitch within the first 55 minutes. Eze encouragingly took a seat on the bench but Kai Havertz made a beeline straight for the changing rooms after going down in the first half. Arsenal only have four days to prepare for a trip to Atlético Madrid in the first leg of the Champions League semifinals. With only a handful of matches remaining, Mikel Arteta threatened to have stumbled upon his first-choice frontline; the technically gifted trio of Eze, Havertz and Martin Ødegaard complemented by a direct outlet on the right wing. Now the Gunners are left to sweat on the fitness of half that lineup. They can at least take solace from a return to the Premier League summit but the focus of north London will be split between Manchester and their own treatment room.…