HOUSTON -- Houston Rockets guard James Harden was quick to reference accountability in the wake of the firing of coach Kevin McHale, and in between the sudden dismissal that shocked the NBA and his postgame reflection, Harden showcased how dangerous he is when engaged.

Harden posted a double-double and engineered a breathtaking comeback, leading the Houston Rockets to a 108-103 overtime victory over the Portland Trail Blazers on Wednesday night at Toyota Center.

Harden finished with 45 points and 11 assists plus eight rebounds and five steals, scoring 26 points in the fourth quarter and overtime to help the Rockets (5-7) snap a four-game losing streak in the debut of interim coach J.B. Bickerstaff. Harden poured in 17 points during the Rockets' 38-point fourth quarter and followed that with a pair of baseline jumpers in the extra period that secured the lead for good.

Afterward, Harden acknowledged that more than a coaching change was in order.

"Something had to change and I felt like for me, I had to change in order for us to be more positive, get more energy," Harden said. "Whatever happened this morning, my mindset coming in today was just to be great at what I do, and that's being a leader and bringing great support on the team."

Trail Blazers guard C.J. McCollum finished with 19 points and hit what appeared to be a backbreaking 3-pointer with 4:54 left in regulation after two free throws by guard Damian Lillard (23 points) halted an 8-0 Rockets run. Houston had clawed to within 83-81 before the Lillard free throws and the McCollum trey bumped the deficit to seven.

But the Rockets wouldn't relent. Harden sank a 3-pointer with 38.6 seconds left to cut the deficit to 97-94 and, after Trail Blazers forward Al-Farouq Aminu (16 points, 15 rebounds) made two free throws with 6.6 seconds left to rebuild the lead to three, Rockets swingman Corey Brewer (16 points) nailed a running 30-footer with 0.9 seconds remaining to send the game to overtime tied 99-99.

Rockets center Dwight Howard grabbed 19 rebounds and forward Trevor Ariza added 18 points and eight rebounds. For Houston, the comeback was a reversal of fortune following a string of ugly losses.

"It's good. It's what we needed," Bickerstaff said. "And the way it happened I say is the way we needed it to happen."

Guard Allen Crabbe scored 13 of his 15 points in the second quarter for Portland (4-9), which dropped its seventh consecutive game.

Even with the Trail Blazers committing eight turnovers in the first quarter, the best Houston could muster with a five-point lead at 22-17. And no matter how much scrambling the Rockets did defensively, they could not overcome their woeful second-quarter shooting (4 of 25) and an inability to locate Crabbe in the corners.

Crabbe nailed three treys by the 5:07 mark of the second quarter, with his third lifting the Blazers to a 34-31 lead. Houston later went nearly four minutes without a basket and Portland closed the half with an 11-2 run.

Portland bumped its advantage to 69-52 on an Aminu turnaround with 2:38 left in the third and things started to feel familiar for the Rockets. But they mustered one last -- and surprising -- gasp in the fourth quarter, setting the stage for the heroics they'd been lacking.

"They had a lot of momentum and we couldn't hit our shots," Portland coach Terry Stotts said. "We didn't shoot the ball well in the fourth quarter. You can't give up 38 points in the fourth quarter. Bottom line, we weren't able to close them out."

Said Trail Blazers guard Gerald Henderson of Harden: "He played like himself. He's proven to be a clutch player, and he's made a lot of big plays. He did it tonight again."

NOTES: With the Rockets firing coach Kevin McHale earlier on Wednesday, Houston assistant J.B. Bickerstaff was elevated to interim head coach and began the process of initiating what he hopes is a turnaround. "It's to get back to who we were, who we've been," Bickerstaff said of his plan. "Who we were when we had our most success." ... Trail Blazers coach Terry Stotts can identify with the position Bickerstaff finds himself in, having served as interim coach with the Atlanta Hawks after Lon Kruger was fired 27 games into the 2002-03 season. "You don't worry about any of that, you just prepare for each game," Stotts said of the interim tag. "The work keeps you pretty occupied. I know J.B. is going to be working his tail off." ... Houston players took the brunt of the blame after McHale was dismissed, primarily for their lack of defensive effort. They didn't shy from that burden. "We are responsible. Coach can't make us play hard," Rockets G/F Corey Brewer said. "That's up to us. It's got to be a wakeup call. We've got to get better. It's about winning."