The Dallas Mavericks started slow but overcame a seven-point deficit at half-time to beat the San Antonio Spurs 115-104.
The Spurs were up early but the Mavs came back, outscoring their opponents 63-45 in the second half to seal their fourth win in a row.
DeMar DeRozan was the top-scorer for San Antonio, hitting 30 points while Kristaps Porzingis scored 28 for Dallas and Luka Doncic added 22.
Memphis kept up their chances in a tight Southwest Division, with the victory seeing them one game behind leaders San Antonio.
Valanciunas also had 20 rebounds, while Ja Morant added 21 points as the Grizzlies defence restricted this season's average-points-per-game leader Bradley Beal to just 21 points on the night.