The Wanderers keeper made some sensational saves to deny the rampant Tigers, who threw everything at the visitors. Ever since they lost at Chelsea, this is their third defeat in a row.
But it simply was not enough as Matt Taylor's 51st minute strike separated the sides.
Hull boss Phil Brown hailed Jaaskelainen's performance. He said: "He's had a blinder
"He pulled off a couple of great saves, with the one from the Geovanni header the turning point.
"But he had one of those days, although he is a world-class 'keeper anyway, and I've nothing but admiration for him.
"He is certainly one of the best in the Premier League, and that's the standard we have to attain.
"He has been around for 10 or 11 years now, and I remember a number of sterling performances like that when I was at the club."
Bolton manager Gary Megson also singled out Jaaskelainen.
He said: "Jussi will get the headlines, and rightly so because his performance was unbelievable, as good as you are ever going to see.
"Some of his saves, like the one from the free kick - which was bad defending from ourselves - at point-blank range was good enough.
"But to then spring onto his feet and palm it away from the other forward coming in was top-class goalkeeping.
"There are some good goalkeepers throughout the world, and we certainly wouldn't swap him for anybody.
"He is not just a terrific goalkeeper, but a good lad, a good pro, and everything that comes his way he deserves because he works his socks off in training."
Hull had fielded all their lethal attackers including the dangerous Geovanni supporting strikers Marlon King and Daniel Cousin.
It was the Brazilian who had the first chance with a low 25-yard shot that Jaaskelainen smothered. As usual, when Bolton does something extr ordinary away from Reebok, Kudos always goes to Jaaskelainen. Hull was so dominant everyone gave them the game especially considering their form and wonders they created so far in the league.
Despite Hull's domination, it was Bolton who took the lead on 51 minutes. Bolton Carried the day and all Kudos to their goalie who worked so hard.
Earlier on, Manchester United full of confidence visited and injury ravaged Arsenal side with confidence at an all time low.
Arsene Wenger admitted his team's bid would have been dead in the water if they had failed to win at the Emirates against United on Saturday after.
That was on an all time low of confidence having lost a 2 goal advantage to spurs, lost to stoke and held to a goalless draw against Fernabache all within 10 days would have found it difficult if they didn't win.
Nasri got the opener on 22 minutes thanks to a deflection off United skipper Gary Neville.
He made it two after a sublime passing move found him on the edge of the box where he hammered home.
Brazilian youngster Rafael Da Silva grabbed a late consolation for United.
United's Michael Carrick fired wide from the edge of the area before Dimitar Berbatov had a goal ruled out for offside.
Arsenal striker Nicklas Bendtner headed over from Gael Clichy's cross and Abou Diaby had a clear sight of goal but his effort was blocked by Carrick. In my opinion Arsenal should have scored at least 5 goals with Rio's poor defending if Nicholas Brendtner was worth the confidence reposed on hi my Arsene. He wasn't just there. They game should have ended 5-2.
Wayne Rooney wasted Cristiano Ronaldo's intelligent cut-back when he smashed over on 17 minutes.
And he was made to pay when Nasri netted the opener just minutes later.
Patrice Evra fouled Bacary Sagna on the right wing and Cesc Fabregas' set-piece was only cleared to Nasri on the edge of the box.
The France star's powerful drive took a wicked deflection off Gary Neville and flew past Edwin Van der Sar in the United goal.
Ronaldo almost replied when his free-kick was nearly clipped in off Clichy. But unitl Rafeal came on to do what Ronney Berbatov and Tevez couldn't do, the game was heading to 2-0 especially with 6 minutes of added time that followed ALumnia's prolonged treatment time on the pitch. Can Arsenal Start getting consistent and take the battle to Aston Villa and Chelsea?