Kengis was eight-time Latvian Champion (1984, 1987, 1988, 1989, 1990, 1997, 2004, 2005). He won Baltic Chess Championship at Pärnu 1985, and shared 1st with Alexander Shabalov and Alexander Malevinsky, at Haapsalu 1986.
He won at Boston open 1989, tied for 2nd-4th at Lloyds Bank open 1990, won Estonian National Championship in Pühajärve in 2001,, tied for 3rd-5th at Kilingi-Nõmme (EST-ch, Kaido Külaots won), won Golden Kleopatra in Egypt in 2003, won I Jyri Vetemaa Memorial tournament at Pärnu 2004.
Kengis six times represented Latvia in Chess Olympiads (1992-1998 and 2002-2004), once in the 3rd World Chess Team Championship at Lucerne 1993, and twice in the European Team Chess Championship at Pula 1997 and Leon 2001. He was awarded the GM title in 1991.