Sight unheard, the Philadelphia Orchestra’s program this week was a pleasant-enough collection of this and that — a nice, little-known Haydn overture, the Mendelssohn Piano Concerto No. 1 played by the increasingly mature (and tall) Jan Lisiecki, and Schubert’s grand Symphony No. 9.

But as is his inclination, music director Yannick Nézet-Séguin ambushed more-probing ears with covert connections between the pieces, creating fresh contexts for these revisited classics.

“Worlds within worlds within worlds" might’ve been an appropriate title for this Thursday program (also scheduled for Carnegie Hall on Friday before returning home Saturday and Sunday), in which Haydn and Schubert turn many corners and find different avenues leading to tragedy.

Haydn’s L’isola disabitata recaps the stormier gestures of music of the 1770s as the piece promenades into a shipwreck. Schubert, in contrast, contemplates less resolvable life traumas.

Nézet-Séguin seemed determined that Schubert’s four movements wouldn’t be isolated musical islands but a larger, forward-moving narrative. The stark but sturdy musical pillars in the first movement gave way to an idiosyncratically marching second movement that morphed into something more relentless and menacing.

The shattering, masterfully built climax was suitably powerful, and the reassembling of the thematic pieces (which can never be the same) was more so. The waltzing third movement had a particularly glittering Viennese lilt until the especially pronounced bass suggested darkness that lay around the corner.

The final movement’s many thematic reinteractions can seem needlessly repetitive in less capable hands, though here a breathless, anxious treatment of the rhythm created edge-of-the-seat suspense.

Rooted in the wide-open key of C-major, the broadly etched Schubert symphony easily mirrors the conductor’s psyche. And though no radical diagnosis was to be had from Nézet-Séguin, the interpretation was the work of a conductor who was going to have it all — crisp tempos and strong pulse of the current historically informed performance movement, the grandeur of his mentor Carlo Maria Giulini (1914-2005), and the emotional candor of the great Wilhelm Furtwangler (1886-1954).

Nothing was done for mere effect. Once a chord did its job, it got out of the way. This was among the best Schubert 9ths of my experience.

So where did Mendelssohn fit? Well, Lisiecki just released a Deutsche Grammophon recording of the concerto, though Thursday’s performance was better on every level — as far as this limited music allows. The concerto’s one-dimensional Biedermeier qualities showed the status quo over which Schubert triumphed.

Lisiecki gave the music high-romantic urgency, though Lang Lang in his younger years showed how a veneer of Mozartean charm can be a better way to go. But in the middle movement, Lisiecki reminded you that some of Mendelssohn’s best music lay in his less self-conscious transitions, responding with a Chopin-esque lyricism and elasticity.

The encore, Mendelssohn’s “Venetian Gondola’s Song,” had the kind of texture that showed the pianist’s considerable poetic imagination.

CLASSICAL REVIEW

Mendelssohn and Schubert

The Philadelphia Orchestra repeats the program at 8 p.m. Saturday and at 2 p.m. Sunday at Verizon Hall. Tickets: $47-159. Information: 215-893-1999 or philorch.org.