Bielsa was frustrated by his team's failure to regularly maintain possession in midfield, while he never felt confident of securing the three points after Marseille went 2-1 ahead, as Metz spent long periods camped in the home side's half.
While Dimitri Payet scored a match-clinching goal for Marseille in second-half stoppage time, Bielsa claimed there was little to like about his side's performance.
"It's a game where we struggled to play well," the Argentine coach said.
"Winning, that was necessary; [it] provides satisfaction - more to the result than the manner."
The statistics did not exactly back up Bielsa's appraisal of the match - Marseille had 62 per cent possession and took 16 shots to Metz's 14 - but the 59-year-old coach was clearly unimpressed.
After Andre-Pierre Gignac gave the home side the lead with a header two minutes before half-time, Florent Malouda equalised for Metz with a deflected effort in the 46th minute.
Marseille hit the front again just before the hour-mark, with Andre Ayew converting after Alaixys Romao hit the post, before Payet wrapped up the win in the 92nd minute with a delicate chip.
"In the second half we improved just after the equaliser. At 2-1, the game was balanced until the end," Bielsa said.
"Metz has been in our camp and we counter-attacked. We had dangerous actions but our way of playing was not clear."
Bielsa added: "We managed to have counter-attacks in the first half but we lost the ball too much in the middle."
The win took Marseille back to the top of Ligue 1 with 38 points, one ahead of reigning champions Paris Saint-Germain, while Metz (19) sit 13th after their winless run extended to five games.