Marcus Mariota got the better of Jameis Winston in their lone on-field meeting. Winston then one-upped Mariota in the NFL Draft.

Which of the two Heisman Trophy winners is currently ahead of the other will be determined when both quarterbacks make their NFL debuts in Sunday's game between Winston's Tampa Bay Buccaneers and Mariota's Tennessee Titans.

The showdown of the draft's top two picks is one of several parallels between the clubs, both of which are striving for major improvements in their second years under head coaches that have taken teams to Super Bowls. The Buccaneers' 2-14 mark in Lovie Smith's inaugural season was the franchise's worst since 1986, while the Titans' two wins in Ken Whisenhunt's debut were their fewest since their days as the Houston Oilers in 1994.

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Accordingly, both have undergone significant offseason changes and enter Raymond James Stadium fielding noticeably young lineups.

Tampa Bay's first four draft picks all earned starting jobs during the preseason, with left tackle Donovan Smith and right guard Ali Marpet part of an overhauled offensive line protecting Winston and Kwon Alexander tabbed to man the important middle linebacker spot in Smith's Cover 2 defense. Mariota is one of eight projected Tennessee starters with two or less years of NFL experience.

There's a wealth of seasoning on Whisenhunt's staff, however, following February's hire of longtime Pittsburgh Steelers coordinator Dick LeBeau as a defensive assistant.

Still, the intrigue of a matchup of the league's two worst teams from last season centers around the rookie quarterbacks' first head-to-head meeting since Mariota led Oregon to a 59-20 Rose Bowl victory over Florida State in January's College Football Playoff semifinals, handing Winston his only loss in 27 starts.

"People will obviously try to make debates and opinions on what's going on, but I'm focused on what our team has to do and preparing for Sunday," Mariota said.

Mariota had the statistically more impressive preseason of the two, completing 70 percent of his throws and producing a 102.9 passer rating while displaying command of an offense with few similarities to the spread attack he excelled in at Oregon. Winston completed just 23 of 47 passes without a touchdown and was sacked seven times in three games.

Mariota will be operating behind a revamped front line after the Titans released right tackle Michael Oher, traded guard Andy Levitre to Atlanta last week and had stalwart left tackle Michael Roos retire after 10 seasons. Free agent pickup Harry Douglas, a 1,000-yard receiver with Atlanta in 2013, and physically imposing rookie Dorial Green-Beckham join Kendall Wright (57 catches, 715 yards, 6 TDs) and tight end Delanie Walker (63 catches, 890 yards, 4 TDs) to give Mariota an array of targets.

Tampa Bay's most notable change on defense will be that Smith will handle play-calling responsibilities himself in an effort to bolster a unit that finished 28th against the pass and tied for 21st with 36 sacks in 2014.

''That's totally unacceptable,'' Smith said of last season's performance. ''We haven't played the type of defense we need to. When we do, that will change.''

The Titans were even worse on that side of the ball, ending 27th in total defense (373.0 ypg) and 31st against the run (137.2 ypg) while permitting 27.4 points per game. Three-time Pro Bowl outside linebacker Brian Orakpo, cornerback Perrish Cox and safety Da'Norris Searcy were brought in as intended upgrades in addition to zone-blitz guru LeBeau, whose multitude of pressure packages should provide a stern first test for Winston.

"Hopefully we can cause him some problems,'' LeBeau told the Titans' official site. "The way the college game is, (quarterbacks) get to see all the looks, but I don't think he has seen all the looks that he is going to see in the NFL."

Winston said he'll be ready for the task.

"It's kind of a common thing, you have a rookie quarterback, you're going to see a lot of pressure," he said. "I definitely accept that challenge. We saw (in preseason) what we're definitely going to see during the season."

Winston does have the luxury of a pair of 1,000-yard receivers at his disposal in second-year pro Mike Evans (68 catches, 1,051 yards, 12 TDs) and veteran Vincent Jackson (70 catches, 1,002 yards, 2 TDs) and will be facing a defense without two key starters in cornerback Jason McCourty (hernia surgery) and nose tackle Sammie Hill (knee surgery).

Tennessee, 8-2 all-time against the Buccaneers, makes its first visit to Tampa since a 13-10 loss in 2007. The Titans earned a 23-17 home win in the last meeting in 2011.