What happened?

Shares of Advance Auto Parts (AAP 0.68%), a leading automotive aftermarket-parts provider for professional and do-it-yourself customers, are up 8% as of 11:00 a.m. EST Tuesday after the company released better-than-expected third-quarter results.

So what

Sales increased 4.3%, to $2.3 billion, during the third quarter, topping analyst estimates calling for $2.2 billion. Advance Auto Parts' (AAP's) top-line growth was driven by a 4.6% increase in same-store sales, much stronger than analyst estimates of 2.5% same-store sales growth. Adjusted earnings per share jumped 32.2% higher, to $1.89 per share, beating analyst estimates calling for $1.76 per share.

Man shopping in the aisle of an automotive aftermarket store, holding a container in his hands.

Image source: Getty Images.

In a press release, Tom Greco, President and Chief Executive Officer said: "I am extremely pleased to report another quarter of improved top and bottom line growth in the third quarter. Through the dedication of our Team Members and our unrelenting focus on enhancing our Customer Value Proposition, we delivered our strongest comparable sales growth in nearly eight years.

Now what

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AAP data by YCharts.

Although AAP only has moved 9% higher over the past three years, the third quarter puts the finishing touches on a 122% gain over the past 12 months. Management also has made progress on other metrics, with third-quarter free cash flow up 140% and adjusted gross margin improving 86 basis points, to 44.3% of net sales.

In fact, the strong third quarter gave management enough confidence to raise full-year guidance: It now expects sales to check in between $9.55 billion to $9.6 billion, up from the prior range of $9.3 billion to $9.5 billion, and for same-store sales to rise 2% to 2.5% compared to the prior guidance range of flat to 1.5% gain.

After a sluggish 2017, management's turnaround efforts appear to be taking hold, as the company's margins and same-store sales continue to improve. Although there's still work to be done, the company is on the right track.