Summerville scored the game-winning goal for Leeds in last week's unexpected victory at Liverpool, and he then scored another key goal to give Jesse Marsch's team back-to-back victories.
After James Tavernier and Philip Billing successfully negated Rodrigo's opening penalty, Bournemouth lead 2-1 at halftime.
At halftime, some Leeds supporters booed the team out, and things appeared gloomy for the home team until Dominic Solanke gave Bournemouth a 3-1 lead early in the second half.
However, Leeds' captain Liam Cooper and substitute Sam Greenwood both scored a goal as a last-minute equalizer before Summerville scored the game-winning goal with six minutes left.
Rodrigo's third-minute penalty gave Leeds a strong start and the lead.
Within the first 60 seconds, Marcos Senesi knocked Summerville to the ground in the penalty area, and Rodrigo scored his sixth premier league goal of the campaign from the spot.
Four minutes later, on their first attempt, Bournemouth equalized. Having only been able to head Billing's cross to the back post, Tavernier sidefooted a shot into the bottom corner while going unmarked.
The 18th minute strike from Bournemouth silenced Elland Road as Leeds goalkeeper Illan Meslier of Leeds pushed Jefferson Lerma's header over the crossbar as Bournemouth rushed into the advantage.
Tavernier's shot was stopped by Meslier, but the rebound fell to the Bournemouth winger, who passed it back to Billing, who slammed the visitors ahead 2-1 from just inside the box.
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As Leeds were once again disorganized at the back following another quick counterattack, Kieffer Moore missed a golden opportunity to double the Cherries' lead when he shot weakly at Meslier right in front of goal.
Three minutes into the second half, Bournemouth again caught Leeds off guard in transition, increasing their advantage.
Tavernier was given too much room on the left, and Solanke converted a low cross to make it 3-1 for the visitors.
Shortly after, Marsch substituted Greenwood for Marc Roca, and it paid off when the replacement curled home a fantastic finish from 20 yards after Pascal Struijk's attempt was blocked.
Before Leeds' captain Cooper raised the Elland Road roof by heading in Greenwood's corner in the 68th minute, Rodrigo missed an opportunity as Leeds pushed for an equalizer.
Moments after replacing Ryan Fredericks, Jack Stacey came within a whisker of putting Bournemouth back in front as the outcome of a typically unpredictable match at Elland Road hung in the balance.
And Leeds was the team who snatched the win. Willy Gnonto, who had come on at halftime, drove at the heart of Bournemouth's worn-out defense and slipped in Summerville, who quickly scored his third goal of the campaign.
Elsewhere in the Premier League
-Last-gasp In a game plagued by a VAR controversy, Mathias Jorgensen's own goal wins Forest a draw against Brentford.
In yet another VAR-related issue, Mathias Jorgensen's own goal in stoppage time gave Nottingham Forest a chance to salvage a 2-2 draw with Brentford.
In the sixth minute of additional time, Jorgensen watched a clearing deflect off him and cross the goal line to give Forest a well-earned draw.
After Morgan Gibbs-White gave Forest the lead, it appeared as though the hosts would leave empty-handed as goals from Bryan Mbuemo and Yoane Wissa set the Bees on course for their first away victory of the year.
However, Mbuemo's goal right before halftime was highly contentious because it was scored from the penalty spot after referee Andre Marriner ultimately determined that Dean Henderson fouled Wissa despite not awarding a live decision and the goalkeeper appearing to have played the ball.
Wissa's goal with 14 minutes left added to Forest's sense of unfairness after two legitimate penalty appeals were turned down by VAR, but there was still one dramatic moment left when Jorgensen's own goal was recognized by goalline technology.
Despite still being in last place, Forest is only two points away from safety with one more home game left before the world cup vacation, thus this could up up being a crucial development in their fight for survival.
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Alphonsus Odumu 1 w
Summerville