The biggest news from Tesla's (NASDAQ:TSLA) update on third-quarter deliveries was undoubtedly its worse-than-expected Model 3 production. With just 260 Model 3 units produced, Tesla missed its target for third-quarter Model 3 production for 1,500 units by a longshot. But there was one area investors may want to take a second look at: Model X deliveries.

Quarterly deliveries of the late-2015-introduced Model X hit a new high in Tesla's third quarter, coming closer to rivaling Model S sales. The higher deliveries show how Tesla has been able to replicate the success its Model S has seen -- but this time in the important luxury SUV market.

Model X with falcon wing doors open

Model X. Image source: author.

Here's a close look at Tesla's third-quarter Model X deliveries.

Record Model X deliveries

For its third quarter, Tesla said it delivered 11,865 Model X units, up 19% sequentially and 168% year over year.

Bar chart showing Tesla's quarterly Model X deliveries.

Data source: Tesla's quarterly vehicle delivery updates and shareholder letters. Table by author.

The quarter's record Model X deliveries followed a surprising pullback in Model X deliveries in Q2. In Q2, Model X deliveries were down 13% sequentially. In addition to these 11,865 Model X deliveries, Tesla delivered 14,065 Model S and 220 Model 3.

With nearly 12,000 Model X deliveries during the quarter, Tesla has officially achieved a goal it set out for itself before Model X deliveries started. Before the final unveiling of Tesla's Model X in 2015, Tesla CEO Elon Musk told CNBC that he believed the new SUV had the potential to double the electric car maker's sales volume. At the time, Tesla was delivering about 11,500 Model S on a quarterly basis.

With complex technology like its unique and difficult-to-manufacture falcon wing doors, self-presenting front doors, and the largest glass windshield in any vehicle, there was good reason to doubt Tesla's ability to ramp up sales and deliveries of the SUV. Even Tesla admitted to "hubris in adding far too much new technology to the Model X in version 1." The overly complex Model X led to significant production challenges early on.

But with quarterly Model X deliveries now double Tesla's level of quarterly Model S deliveries two years ago, Tesla's Model X -- falcon-wing doors and all -- is just as important to Tesla's business as Model S.

Tesla Model X and Model S in a Tesla store

Model X and Model S. Image source: author.

Looking ahead

With several recent catalysts positioned to help Model X sales, there may be more Model X sales growth ahead. Not only did Tesla recently lower the price of its entry-level Model X, but it also finally beefed up its display and test-drive Model X units to adequate levels. Until Tesla's second quarter, stores were operating with "far short of what was needed," according to Tesla.

Further, Tesla's guidance for strong combined Model S and X deliveries in the second half of the year support the case for further growth. In its update on third-quarter vehicle sales, Tesla said it now expects to deliver a record 27,000 Model S and X units in its fourth quarter.

Daniel Sparks owns shares of Tesla. The Motley Fool owns shares of and recommends Tesla. The Motley Fool has a disclosure policy.